fastplyr 0.9.0

New features

Many common expressions, such as sum(), mean() and many others have been
optimised in functions like f_summarise(). For a current list of
optimised functions, see ?f_summarise.

• f_mutate as an alternative to mutate

• f_reframe as an alternative to reframe

• Fast group metadata helper functions f_group_data, f_group_indices,
  f_group_keys, f_group_rows, f_group_size and f_n_groups.

Bug fixes

• Joins involving columns of non-standard vectors would sometimes fail to join
  correctly in rare circumstances. This has now been fixed.