tidybayes: Tidy Data and Geoms for Bayesian Models

Fixed errors on CRAN from changes in dplyr New features and documentation: Initial support for add_residual_draws, towards #133 Add tidybayes-residuals vignette Add adddraws to support models that add[fitted|predicted]_draws does not (closes #149) Add sample_draws to make it easier to take fewer draws anywhere in the pipeline (towards #144) Add hypothetical outcome plots (HOPs) to examples Minor changes: Fix bug to support multivariate models in predicted_draws, closes #134 Add support for emm_list in gather_emmeans_draws, closes #126 Default for show.legend no longer omits all guides Make default lineribbon color black, closes #15