Update lita.io links for https. [ci skip]
Use a double for the source in the message spec.
Add Message#reply_with_mention.
Implement Robot#send_messages_with_mention.
Implement User#mention_name.
Implement Adapter#mention_format.
Delegate reply methods from Response to Message.
Disable broken SpaceBeforeFirstArg cop in RuboCop 0.20.0.
Enable SpaceBeforeFirstArg cop which was fixed in RuboCop 0.20.1.
Bump version to 3.1.0.