Version 0.9.1

+ Fix str_title_case to grep with Perl syntax.
+ Expand tests
Version 0.9.2

Many refinements added mostly to make the functions more composable.
Improvements to str_is* functions.

- Now str_is compares string == fun(string) for generic handling of
comparisons.
Begin move to using stringr and magrittr
Minor modifications
Move make_names to the conformist package; make_names feels out of scope
Fix docs
Version 0.10

+ Standard on str_lowercase and str_uppercase as main function.
+ Add alias for str_lower, str_upper, is_lower, is_upper
+ Fix check warnings
+ Import %>% from magrittr