Add count_by() and find_last()
Merge pull request #5 from nathancahill/master

Fix pull() to change the list instead of creating a new one
Make _iter_list_callback and _iter_dict_callback generators.
Add reduce_(), foldl(), inject(), reduce_right(), and foldr().
Fix Python 3 compat
Merge pull request #6 from nathancahill/functions

Add count_by() and find_last()
Merge pull request #7 from nathancahill/master

Switch from try/except to while count(value) > 0