Cleverbot.py

Changes
- Made Cleverbot picklable
- Added migrations
- Changed nameless conversations to be weakly stored
- Fixed `Cleverbot.reset` erroring without conversations

Changes
- Added a command line interface
- Changed the async `Cleverbot.close` to a coroutine

Changes
- Added \_\_slots__ to Conversation
- Added deleters to Conversation properties
- Added the ability to pass filenames into save and load

Changes
- Added a persistent tweak setting to change Cleverbot's mood more easily
- Fixed error on save if there were no conversations

Changes
- Fixed tests not being included in the source

Changes
- Added conversations
- Added the ability to save and load Cleverbot and its conversations
- Added tests
- Made async_ easier to work with