Implement leaving conversations
Add missing 'import datetime' to client.py
Fix differentiation between group and one-to-one conversations when leaving conversation
Fix ConversationType import
Implement support for sending typing notifications
Fix TypingStatus import in __init__.py (need to be before imports from client.py)
Merge remote-tracking branch 'xmikos/master'
Remove unnecessary import
Comment about set_typing needing rate-limiting
Rename ConversationList method for leaving