                    *************************
                    ** afex VERSION 0.27-x **
                    *************************
                    
                    Changes in afex Version 0.27-x
                    Released March 2020
                    
    Significant User Visible Changes and New Features
    
    o   p-values are now per default rounded to 3 digits following APA 
        recommendations, thanks to Marius Barth: 
        https://github.com/singmann/afex/issues/81
        To achieve this, a new argument, round_ps, was added to nice() which 
        accepts a rounding function and defaults to round_ps_apa() via 
        afex_options("round_ps"). To reset to the old rounding behaviour, call:
        afex_options(round_ps = round_ps)

    o   New p-value rounding function round_ps_apa().  

    Bugfixes

    o   mixed(): check_contrasts = TRUE now works when the formula is not a 
        formula (but e.g., a character string).
        
    o   Better error message when ANOVA formula does not include an errror term.
    
    o   Should work with both lme4 1.1-22 and later.


                    *************************
                    ** afex VERSION 0.26-x **
                    *************************
                    
                    Changes in afex Version 0.26-x
                    Released January 2020
                    
    Significant User Visible Changes and New Features
    
    o   factor_levels argument of afex_plot() now accepts named character vectors
        which allows: 
        (1) renaming only a subset of factor levels (if only a subset of levels 
            is specified) 
        (2) reordering in which order factor levels are shown in the plot (order
            of names within a list element determine order that will be used for
            plotting)

    Bugfixes

    o   msq data set is now part of psychTools and not of psych. 
        Fixes CRAN check issues.


                    *************************
                    ** afex VERSION 0.25-x **
                    *************************
                    
                    Changes in afex Version 0.25-x
                    Released August 2019
                    
    Significant User Visible Changes and New Features
    
    o   Better error messages for ANOVA in some case in which data shows 
        structural problems (e.g., missing design cells).
        
    o   afex_plot() now first draws all graphical elements belonging to a 
        specific factor level, before drawing graphical elements belonging to 
        the next factor level in interaction plots (does not apply to data in 
        the background). This avoids inconsistencies in plotting order between
        error bars and connecting lines.
        

    Bugfixes

    o   Correct Type III ANOVA results for character variables if 
        factorize = FALSE.
        
    o   afex_plot() for mixed or merMod objects uses actual dv on y-axis.
    
    o   afex_plot() x-labels and legend-title display correctly in case more 
        than one variable is displayed.
        
    o   The default method for afex_plot() can now aggregate via the id argument 
        even if the corresponding factor is only part if the random effects 
        terms (see rstanarm examples in vignette).
        
    o   Removed certain non-ASCII characters in examples:
        https://github.com/singmann/afex/issues/66



                    *************************
                    ** afex VERSION 0.24-x **
                    *************************
                    
                    Changes in afex Version 0.24-x
                    Released July 2019
                    
    Significant User Visible Changes and New Features
    
    o   Added possibility to suppress calculation of aov object for ANOVAs, via
        argument 'include_aov' (with default = TRUE). Suppressing the 
        calculation of the aov object can significantly reduce estimation 
        time of ANOVAs for models with large N and within-subjects factors. Even 
        for small models, a speed increase by more than 10% is expected.
        For ANOVAs without aov object, emmeans are always based on the 
        multivariate or lm model. 

    o   Added test_levene() and test_sphercitiy() functions for assumption tests
        for ANOVA models. Thanks to Mattan S. Ben-Shachar. Addresses #55, 
        https://github.com/singmann/afex/issues/55

    o   afex now depends on R (>= 3.5.0), as it uses binary/serialized objects 
        version 3.

    Bugfixes

    o   Sum-to-zero contrasts will now be set to all character variables 
        passed to mixed(). Before, only factor variables were assigned 
        sum-to-zero contrasts and transformation into factors happened only in 
        the call to model.matrix() (which then used the global contrasts).


                    *************************
                    ** afex VERSION 0.23-x **
                    *************************
                    
                    Changes in afex Version 0.23-x
                    Released February 2019
                    
    Significant User Visible Changes and New Features
    
    o   Added afex_plot.default() method which works with a wide variety of 
        fitted objects. See new vignette:
        vignette("afex_plot_supported_models", package = "afex")
        
    o   In afex_plot(), renamed 'random' argument to 'id' argument.
    
    Bugfixes

    o   Corrected bug in afex_plot() vignette and examples. Correct argument
        name is factor_levels.

    o   Removed reference to ascii package from documentation, as the package 
        was removed from CRAN.


                    *************************
                    ** afex VERSION 0.22-x **
                    *************************
                    
                    Changes in afex Version 0.22-x
                    Released September 2018
                    
    Significant User Visible Changes and New Features
    
    o   New functions for plotting results (means, error bars, and raw data) 
        using ggplot2, afex_plot(), generic function for afex and lme4::merMod 
        objects. Furthermore added two more functions:
        - interaction_plot(): workhorse producing interaction plot
        - oneway_plot(): workhorse producing oneway plot
        Error bars can display confidence intervals (the default) or standard
        errors and can be calculated using a variety of different standard 
        errors (e.g., model-based, within-subjects).

    o   Added vignette introducing afex_plot().
        
    o   Updated ANOVA vignette to use afex_plot() and the multivariate for 
        follow-up test.
    
    o   Package emmeans was moved to suggests and needs to be either attached 
        explicitly or called with ::
        Option 1: emmeans::emmeans() 
        Option 2: library("emmeans") and then just emmeans()
        
    o   Added call slot to mixed objects holding the matched call.
    
    Bugfixes

    o   Error in ANOVA examples using emmeans corrected, see:
        https://stats.stackexchange.com/q/360900/442


                    *************************
                    ** afex VERSION 0.21-x **
                    *************************
                    
                    Changes in afex Version 0.21-x
                    Released June 2018
                    
    Significant User Visible Changes and New Features
    
    o   Smaller package footprint: 
        The stringr package is not imported any more, all calls to stringr 
        functions were replaced with calls to base R functions.
        The coin package (used in compare.2.vectors) was moved from Imports to 
        Suggests.
    
    Bugfixes

    o   ANOVA functions produce accurate emmeans even for ANCOVAs, see: 
        https://afex.singmann.science/forums/topic/precise-estimates-from-emmeans-across-lm-and-aov_ez

    
    
                    *************************
                    ** afex VERSION 0.20-x **
                    *************************
                    
                    Changes in afex Version 0.20-x
                    Released April 2018
                    
    Significant User Visible Changes and New Features
    
    o   follow-up tests with emmeans for ANOVAs (i.e., objects of class 
        "afex_aov") with repeated-measures factors can now be based on a 
        multivariate model. This provides separate standard errors for each 
        estimate and more adequately accounts for violations of sphericity. To 
        use this model either call emmeans(..., model="multivariate") or set 
        globally via: afex_options(emmeans_model = "multivariate")

    o   ANOVA functions now allow transformations of the dv (thanks to 
        Russell Lenth).
    
    o   better (i.e., simpler) examples for mixed (use data from MEMSS). Added
        example showing how to use mixed() with effects package for plotting.
        
    o   set_data_arg argument of mixed() is now per default controlled via 
        afex_options("set_data_arg"). The default has also changed from TRUE to 
        FALSE. The reason for this change is that FALSE appears to work better 
        with emmeans. 
        
    o   afex_aov objects have received an additional attribute, 
        "incomplete_cases", that contains the IDs of removed participants due to 
        missing values (thanks to Frederik Aust).
        
    o   afex should now work with the upcoming versions of car (3.0) and 
        lmerTest (3.0). The latter thanks to Rune Haubo Bojesen. 
    
    Bugfixes

    o   removed bug in mixed that caused a crash if check_contrasts = FALSE 
        and the data contained missing values in the IVs.
        
    o   removed bug that caused a crash under certain conditions if 
        stringsAsFactors was set to FALSE in the global options and repeated 
        measures factors were present (thanks to Will Hopper for the bug report 
        and simultaneous fix).
        
    o   set_data_arg now works for lmer_alt and mixed(..., return = "merMod"). 
        This allows to use those objects with e.g., the effects package.
        
    o   afex should now work with car version 3.0.

    
                    *************************
                    ** afex VERSION 0.19-x **
                    *************************
                    
                    Changes in afex Version 0.19-0
                    Released January 2018
                    
    Significant User Visible Changes and New Features
    
    o   afex now works with emmeans (successor of lsmeans pckage).
    
    Bugfixes

    o   lsmeans did not work with mixed objects if type=2 and method used nested
        model comparions (e.g., LRT or PB).
        
    o   removed warning 'Error() model is singular' when units of observations 
        have missing values for ANOVAs.



                    *************************
                    ** afex VERSION 0.18-x **
                    *************************
                    
                    Changes in afex Version 0.18-0
                    Released May 2017
        
    Bugfixes

    o   aov_ez did not work with more than one covariate 
    (https://github.com/singmann/afex/issues/29).



                    *************************
                    ** afex VERSION 0.17-x **
                    *************************
                    
                    Changes in afex Version 0.17-x
                    Released April 2017

    Significant User Visible Changes and New Features

    o   Added Satterthwaite approximation (method="S") to mixed(), which is 
        implemented via lmerTest. Satterthwaite approximates the degrees-of-
        freedom of an F-test, similar to the default Kenward-Roger method, but
        requires less RAM.
    
    o   mixed() methods "KR" and "S" are now obtained via tests on the full 
        model directly. No restricted models are calculated for these methods. 
        The former KR method is still available: method="nested-KR"
    
    o   mixed() now per default exports and uses lmerTest::lmer and not 
        lme4::lmer(). This can be changed via calling 
        afex_options(lmer_function = "lme4")
        
    o   afex does not depend on reshape2 any more. It is only imported.
        
    o   All arguments with "." in the name have been renamed to use "_". The old
        names have been deprecated (i.e., still work, but should not be used).
        check.contrasts = check_contrasts, test.intercept = test_intercept,
        args.test = args_test, ...
        
    o   Names of slots of mixed model objects with "." have been renamed to have
        a "_" instead: full.model = full_model and restricted.models = 
        restricted_models
        
    o   afex_options() now uses the global R options accessible via options() 
        (with prefix afex.) and allows to reset all options via list (i.e.,:
        aop <- afex_options(); ...; afex_options(aov); works).
        
    o   renamed allFit() to all_fit() and argument meth.tab to meth_tab. 
        Added method dfoptim::nmkb() to all_fit(). To use nmkb, dfoptim needs to
        be loaded explicitly via library (see examples). 
        
    o   Added argument all_fit to mixed(). If TRUE, each model is fitted with 
        all available optimizers and the best fit in each case selected.
        
    o   mixed objects have an additional slot, "data", that contains the data 
        used for fitting.
        
    o   Added vignette with extensive mixed model example.
    
    o   Created forum for providing afex support: http://afex.singmann.science/
        
    Bugfixes

    o   Sphericity correction now correctly displayed as none if all within-
        factors have only two levels (bug removed by Frederik Aust).
        
    o   removed bug when calling nice() on afex_aov objects created with 
        explicit effect size.
        
    o   aov_...(): anova_table = list(intercept = TRUE) now correctly suppresses
        the intercept (bug removed by Frederik Aust).
        
    o   aov_...(): return = "nice" did not work (bug removed by Frederik Aust).
    
    o   aov_...() now supports column names with spaces (using backticks), see: 
        https://github.com/singmann/afex/issues/22 Thx to Jonathan Love for fix.
        
    o   changed license to GPL >=2 (as it call some function from GPL >=2 
        packages).
        
    o   removed bug that mixed() object with type=2 could not be printed.
    
    o   removed bug that model names for anova.mixed with multiple models were 
        incorrect.
        
    o   all_fit() now uses a data argument correctly and passes it update(). 
        This again allows to use it for data with suppressed correlations. 
        all_fit(... verbose = TRUE) now correctly signals if a fit failed.


                    *************************
                    ** afex VERSION 0.16-x **
                    *************************
                    
                    Changes in afex Version 0.16-x
                    Released April 2016

    Significant User Visible Changes and New Features

    o   added "correction" and "observed" attributes to the anova_table slot of
        afex_aov objects, which is used per default by nice(). This ensures 
        that nice(object) and object always return the same data.frame.
        Also added "nice_table" class to data.frame returned by nice which 
        print the value of the slots for information.
        Both contributed by Frederik Aust (who was also promoted to author).
        
    o   added return="data" for mixed. This allows to obtain the data set used
        for fitting a model. Can be useful in combination with expand.re=TRUE 
        and allFit() or for obtaining predictions. See ?allFit for a simple 
        example.
        
    Bugfixes
    
    o   increased required version of R (>= 3.1.0) and the following packages
        to ensure afex runs with older versions of R: lme4 (>= 1.1-8), 
        pbkrtest (>= 0.4-1), and Matrix (>= 1.1.1).

        
                    *************************
                    ** afex VERSION 0.15-x **
                    *************************
                    
                    Changes in afex Version 0.15-x
                    Released October 2015

    Significant User Visible Changes and New Features

    o   added p.adjust.method argument for ANOVA functions (anova and nice 
        methods). Can be used to control for multiple comparisons in 
        exploratory ANOVAs (see Cramer, et al., 2015; PB&R). Functionality 
        contributed by Frederik Aust (https://github.com/singmann/afex/pull/3).
        
    Bugfixes
    
    o   ANOVA functions work with dplyr data.frames now (data is transformed
        via as.data.frame). See: https://github.com/singmann/afex/issues/6
    
    o   formulas for mixed can now be of a maximum length of 500 characters 
        (was 60 chars previously): https://github.com/singmann/afex/issues/5
        
    o   aov_car et al. did not work with within-subject factors that were also
        included outside the Error term. This was caused by the use of regular
        expressions not appropriate for the new stringi backend of stringr.
        Thanks to Tom Wenseleers for reporting this bug.
    

    
 
                    *************************
                    ** afex VERSION 0.14-x **
                    *************************
                    
                    Changes in afex Version 0.14-x
                    Released August 2015

    Significant User Visible Changes and New Features

    o   new default return argument for ANOVA functions, afex_aov, 
        an S3 object containing the following:
        (1) ANOVA table of class "anova"
        (2) ANOVA fitted with base R's aov (can be passed to lsmeans 
            for post-hoc tests)
        (3) output from car::Anova (for tests of effects),
            ANOVA table (1) is based on this model
        (4) lm object passed to car::Anova
        (5) data used for estimating (2) and (4)
        
    o   added support for lsmeans: objects of class afex_aov can be 
        passed to lsmeans directly. afex now depends on lsmeans.
    
    o   added afex_options() functionality for setting options globally.
    
    o   added expand_re argument to mixed which, if TRUE, correctly interprets 
        the || notation in random effects with factors (i.e., suppresses 
        estimation of correlation among random effects). lmer_alt is a wrapper
        for mixed which uses expand_re = TRUE, returns an object of class
        merMod (i.e., does not calculate p-values), and otherwise behaves 
        like g/lmer (i.e., does not enforce certain contrasts)
    
    o   added three new data sets (Singmann & Klauer, 2011; Klauer & 
        Singmann, 2013) and a vignette showing how to calculate 
        contrasts after ANOVA.
    
    o   ANOVA functions renamed to aov_car, aov_ez, and aov_4. Old 
        functions are now deprecated.
    
    o   first element in mixed object renamed to anova_table.
    
    o   nice.anova renamed to nice. nice() can be called for afex_aov
        and mixed objects and returns a nicely formatted (numbers 
        converted to characters) results table (which is also the 
        default print method for both objects).
        
    o   anova() can be called for afex_aov and mixed objects and returns
        the numeric anova table (i.e., the first element of each object).
        There also exists print methods for those data.frames.
    
    o   summary method for mixed objects now calls summary.merMod on 
        full model.
        
    o   afex does not depend on car package anymore, it is only imported.
        
    o   afex is now hosted on github: https://github.com/singmann/afex
        
    Bugfixes
    
    o   ANOVA: for "aov"-objects, contrasts are only set for factors.
    
    o   compare.2.vector failed when the two means were exactly equal 
        (due to an issue with median_test). This only throws a warning 
        now.
        
    o   compare.2.vector documentation updated for coin 1-1.0.
    

    

                    *************************
                    ** afex VERSION 0.13-x **
                    *************************
                    
                    Changes in afex Version 0.13-x
                    Released January 2015

    Significant User Visible Changes and New Features

    o   added ems() function for deriving the expected values of the 
        mean squares for factorial designs (contributed by Jake 
        Westfall).

        
    Bugfixes
    
    o   aov.car et al. stop with error message if a factor has only one
        level.
        
    o   aov.car transforms id variable to factor which ensures that 
        return = "aov" provides equivalent results.
        
    o   changed regex for detecting "observed" variables to work with 
        the new version of stringr which uses stringi.
    



                    *************************
                    ** afex VERSION 0.12-x **
                    *************************
                    
                    Changes in afex Version 0.12-x
                    Released November 2014

    Significant User Visible Changes and New Features

    o   ANOVA functions give informative error if some parameters are
        not estimable (most likely due to structural missings, i.e. 
        empty cells).

        
    Bugfixes
    
    o   mixed(..., method = "PB") does not fail anymore when only 
        having a single fixed effect (thanks to Kiyoshi Sasaki for
        reporting it). 
        
    o   aov.car() failed when a within-subject factor had empty levels.
        Unused factor levels are now dropped. This bug was probably 
        introduced in Rev 126 as part of an attempt to solve a bug. 
        (thanks to Will Bowditch for reporting it).
    

    
                    *************************
                    ** afex VERSION 0.11-x **
                    *************************
                    
                    Changes in afex Version 0.11-x
                    Released October 2014

    Significant User Visible Changes and New Features

    o   added allFit() function (written by Ben Bolker).
    
    o   mixed() gives warning if nested model provides worse fit 
        (logLik) than full model (when fitted with ML).
    
    o   print, summary, and anova method for mixed objects are now 
        identical.
        
    o   description of returned object from mixed() extended (Thanks
        to Ben Bolker, see http://stackoverflow.com/a/25612960/289572)
        
    o   added return = "aov" to aov.car which returns the ANOVA 
        fitted with aov (with correct Error strata) so that it can be
        passed to lsmeans for post-hoc tests or plotting (lsmip).
        
        
    Bugfixes
    
    o   all required functions are now correctly imported avoiding 
        CRAN warnings and better functioning.
        
    o   data argument to lmer calls in mixed set correctly. Note that
        still contrasts added to the data in mixed may prohibit use of 
        predict.merMod() or similar functions. It is recommended to 
        set the contrasts globally to "contr.sum", e.g., 
        via set_sum_contrasts(), for correct functioning
        (disable via set.data.arg argument for mixed).
        
    
        
                    ************************
                    ** afex VERSION 0.10-x **
                    ************************
                    
                    Changes in afex Version 0.10-x
                    Released August 2014

    Significant User Visible Changes and New Features

    o   afex does not change the global contrasts anymore when loading 
        the package (due to popular demand).
    
    o   new functions to globally set contrasts: set_sum_contrasts & 
        set_treatment_contrasts (and some more wrappers).
        
    o   Added more mixed model examples from Maxwell & Delaney, Chapter 
        15 ("Multilevel Models for within subjects designs"), see ?mixed 
        and ?md_15.1. Thanks to Ulf Mertens. 
        
    Bugfixes
    
    o   removed bug when factor levels of within-subject factors
        contained "+" or "-" and were not converted correctly. Added 
        tests for known bugs in aov.car.
        

                    ************************
                    ** afex VERSION 0.9-x **
                    ************************
                    
                    Changes in afex Version 0.9-x
                    Released April 2014

    Significant User Visible Changes and New Features

    o   added function aov4: another wrapper of car::Anova for ANOVA
        models specified via lme4::lmer syntax.
    
    o   added return="marginal" to aov.car which returns the marginal 
        means of all effects (i.e., grand mean and mean of main 
        effects and interactions). Is also returned if return="full".
        
    o   testing the intercept in mixed models in now only optional.
        The default is that the new argument test.intercept = FALSE.
    
    o   removed return="lme4" from aov.car.
    
    o   added argument intercept to nice.anova (default FALSE) which
        allows to selective display the intercept in an ANOVA table.
        
    o   added method = "F" to mixed() which only returns the F-value 
        but no ddf (and hence no p-value). Experimental, not documented.
     
    o   renamed colname "stat" to "F" when method = "KR" (mixed).
    
    o   added tests (currently mainly for mixed()) via pkg testthat, 
        see tests/testthat.
        
    Bugfixes
    
    o   increased requirement of R version and lme4 version.    
    
    o   print.mixed should now propagate all warnings from lme4 (i.e., 
        also the new convergence warnings).
        
    o   lme4 is now loaded at worker nodes for mixed (default, 
        turn of via check.contrasts)

        

                    ************************
                    ** afex VERSION 0.8-x **
                    ************************
                    
                    Changes in afex Version 0.8-x
                    Released February 2014

    Significant User Visible Changes and New Features

    o   removed renaming of within subject factor levels to names
        with length 1 (which was introduced in 0.6).
        
    o   helper function round_ps which nicely rounds p-values
        is now exported.
        
    o   warning about numerical non-centered variables in mixed
        is now a message only.
        
    o   added examples data sets from Maxwell & Delaney (2004) for 
        within-subjects ANOVA and mixed models.
        
    o   reshape2 is now again in depends but coin only imported.
    
    Bugfixes
        
    o   the default effect size (ges: generalized eta-squared) was 
        calculated wrong (the error term for the intercept was not 
        included). Sorry. This is now corrected (with new examples).
    
    o   removed bug that aov.car didn't work when running some ANCOVAs
        (thanks to Gang Chen for reporting this).

        

                    ************************
                    ** afex VERSION 0.7-x **
                    ************************
                    
                    Changes in afex Version 0.7-x
                    Released December 2013

    Significant User Visible Changes and New Features

    o   nicer output of print.mixed
    
    Bugfixes
    
    o   mixed() correctly converts all non-formula arguments to 
        formula correctly to a formula (gave error if formula
        was a different object and not-available on cluster nodes).
        Prints message if formula is converted to a formula.
        
    o   Using multicore for fitting the models prodcued erroneous 
        results (did not use correct contrasts at nodes). Now the
        current contrasts are also set at the nodes.
        
    o   mixed() sets REML = FALSE if method = "LRT" and no 
        family argument is present (i.e., for LMMs) as LRTs
        for models fitted with REML are not recommended.
        
    o   on the cluster nodes now only the lme4 namespace is 
        loaded (instead of using library) to avoid a CRAN note.


                    ************************
                    ** afex VERSION 0.6-x **
                    ************************
                    
                    Changes in afex Version 0.6-x
                    Released September 2013

    Significant User Visible Changes and New Features

    o   added LRT tests to mixed() which should replicate
        the recommended test by Barr et al. (2013, JML).
        
    o   multicore estimation of (g)lmer models now available
        through package parallel (argument cl) for mixed().
        
    o   added experimental "lme4" return method for 
        aov.car and ez.glm (which fits the data using lmer).
        
    o   reshape2 and stringr are not any more loaded when
        loading afex (are now only imported via Imports)
    
    Bugfixes
    
    o   Type 2 tests of mixed() were implemented incorrectly (i.e.,
        they did not give what they should have given according
        to the description in the help file).
        
    o   aov.car() and ez.glm() now convert factor levels of within 
        subjects factors to be of length one so that long levels 
        do not lead to problems when constructing the call to lm. 
        Thanks to Isaac Schwabacher for noticing this, see also:
        https://bugs.r-project.org/bugzilla3/show_bug.cgi?id=15377
    
    o   mixed should now work with missing values as it construes
        a new data object if the model.matrix from which the
        different versions are fitted has nrow different to 
        nrow(data) (with warning). Thanks to Daniel Bunker
        for reporting this.
        
    o   mixed should work with the newest version of lme4 (>= 1.0.4)
        and the newst version of pbkrtest (>= 0.3-5.1), but not 
        with older versions (due to CRAN policy to disallow :::).

                    
                    ************************
                    ** afex VERSION 0.5-x **
                    ************************
                    
                    Changes in afex Version 0.5-x
                    Released May 2013

    Significant User Visible Changes and New Features

    o   added argument factorize (default: TRUE) to aov.car and ez.glm:
        all variables are now factorized per default. (now it is 
        necessary to set factorize=FALSE for ANCOVAs!)
    
    o   added argument per.parameter to mixed() which allows to specify
        variables for which each parameter is tested (not only the 
        overall effect). Can be useful to test for ordered factors. 
        (only implemented for "Type 3" tests)
    
    o   added more informative startup message (thanks to Robert Volcic 
        and Lars Konieczny)
        
    o   mixed, ez.glm and aov.car now check for correct contrasts and set 
        factors to contr.sum if other contrasts are found (can be tunred 
        off via check.contrasts argument). Resetting the default contrast
        to contr.treatment should therefore not interfere with afex.
        (this is not intensly tested, so please report anything)
    
    o   mixed checks numeric variables if they are centered on 0 (and
        gives warning if not).
    
    Bugfixes
    
    o   checks if observed variable is in the data and throws
        an error if not (nice.anova)


                    ************************
                    ** afex VERSION 0.4-x **
                    ************************
                    
                    Changes in afex Version 0.4-x
                    Released February 2013

    Significant User Visible Changes and New Features

    o   added generalized and partial eta-squared effect
        sizes to nice.anova (this also included adding
        observed arguments to aov.car, ez.glm, nice.anova)        
    
    o   added new return arguments to aov.car and ez.glm
        (nice, lm, data).
    
    o   changed default return value of aov.car and ez.glm
        to "nice" which now returns a nice ANOVA table
        (nice.anova)
    
    o   mixed has method = "PB" for obtaining parametric
        bootstrapped p-values (e.g., for GLMMs)
        
    o   added alternative argument to compare.2.vectors.
    
    o   aov.car (and ez.glm) now give a warning if 
        observations are missing on within-subject factors.
        (As before, cases with missing values are simply
        excluded from the analysis)
    
    o   had to disable saving of the previous contrasts and
        resetting those after detaching afex due to 
        CRAN policies (no assignment in global environment).
    
    Bugfixes
    
    o   Bug when running mixed() inside a function and
        handing the data.frame over as an argument fixed
        (thanks, again, to Florent Duyme). See
        bugs/eval.scoping.bug.R
    
    o   nice.anova did not work with a model with only one 
        within-subjects factor.
    


                    ************************
                    ** afex VERSION 0.3-x **
                    ************************
                    
                    Changes in afex Version 0.3-x
                    Released August/September 2012

    Significant User Visible Changes and New Features
    
    o   added function compare.2.vectors().
    
    o   Name of function univariate() changed to univ(), as
        a function with this name is part of package multcomp.
        This may leed to problems. Thanks to Florent Duyme for
        spotting this.
    
    o   added return argument to aov.car() and ez.glm().
    
    o   added rather dubious Type 2 tests to mixed().
    
    o   aov.car checks if each id is only present in one
        cell of the between subjects design.
    
    Bugfixes
    
    o   aov.car now uses do.call when calling lm() to avoid local
        variables in the call to lm() which could led to problems when
        working with the lm model.
    
    o   mixed() now passes ... (further arguments to lmer) correctly.
        (Now mixed uses match.call and eval on the call instead of 
        invoking lmer directly.)
    
    o   corrected bug that was introduced by pbkrtest v3.2 when 
        invoking the print method to an object of class mixed 
        (again thanks to Florent Duyme for spotting this).
    
    o   removed bug when factor levels of within-subject factors
        were non-legal names (solution uses make.names).
    
