Rate limit support, multiple authentication, search using v1.1 api and more.

Added multiple features (sorry for not separating commits):
- API now support switching between multiple authentication handler
- Allow blocking when reaching rate limit.
- Search is now using Twitter API v1.1
- 'Pagination' of timelines is now done properly with max_id parameter, applies to all endpoints supporting 'max_id'. Other endpoint that have 'page' in their argument list still use the old pagination iterator.
- Fixed an issue with PageIterator that caused the iterator to make an extra call to the Twitter API beyond the provided page limit.
- Add unit tests for all of the above.