Twitter-ads

- Fix to handle inconsistent API response in `PromotedTweet.save()` (jackMort)
- Added `.first` to the `Cursor` class (garethpaul)

- Fixing `Cursor` to handle next cursor and request params correctly. (jackmort)

- Refactor of resource subclasses. (brandonblack)
- Fix for void methods that should be returning `self`. (brandonblack)
- Fix for incorrect return value in `Acccount.load()`. (jackmort)
- Added support for `httplib2` and fixing `http.client` support in Python 3. (thelostscientist)

_Note:_ backward compatibility for deprecated APIs will remain in place until v1.0.0.

Initial Release