tidyverse / forcats

New functions

• as_factor() which works like as.factor() but orders levels by
  appearance to avoid differences between locales (#39).
• fct_other() makes it easier to convert selected levels to "other" (#40)
• fct_relabel() allows programmatic relabeling of levels (#50, @krlmlr).

Minor improvements and bug fixes

• fct_c() can take either a list of factors or individual factors (#42).
• fct_drop() gains only argument to restrict which levels are dropped (#69)
  and no longer adds NA level if not present (#52).
• fct_recode() is now checks that each new value is of length 1 (#56).
• fct_relevel() gains after argument so you can also move levels
  to the end (or any other position you like) (#29).
• lvls_reorder(), fct_inorder(), and fct_infreq() gain an ordered
  argument, allowing you to override the existing "ordered" status (#54).