Created a model for the `Activity` and improved other models.
Multi-channel communication is now working. Still a work-in-progress.
Fixed the channel `created` event.
Implemented publish / subscribe messages.
Migrated signaling messages to channels.
Emitting join event instead of joined.
Rebased with the master branch (v0.4.2)
Handling RPC responses.
Whitespace changes.
Merge branch 'feature/multi-channel'