Fix issue #317 TwythonRateLimitError.retry_after is always None.
Formatting fixes
Update README.rst
Merge pull request #343 from bit2pixel/patch-1

Update README.rst
Merge pull request #342 from dalleng/master

Fix issue #317 TwythonRateLimitError.retry_after is always None.
Changing versions, adding AUTHORS & HISTORY
Update AUTHORS, HISTORY, DeprecationWarning on update_status_with_media
Fixes #305