Implement the SPAChannel class.
Merge with master
Make webrtc model always handle the creation of the data channel and notify interested listeners when a transport is created
Use the SPA model in the chat app, and enable the data channel in webrtc based on if spachannel is in the capabilities or not
DataChannel: queue messages when not ready yet
Merge branch 'master' into spa-channel
Decide which transport to use according to their support
Change the interface for SPA specific messages
Payloads: implement SPAChannelMessage
SPA: forward and listen SPAChannel messages
Fix tests
Increase the tests coverage
Fix jshint errors
Merge branch 'master' into spa-channel

Conflicts:
	static/js/chat/models.js
	static/js/chat/views.js
	test/frontend/chat/callcontrolsview_test.js
	test/frontend/chat/textchatmodel_test.js
Address PR comments
Merge pull request #363 from tOkeshu/spa-channel

SPA Channels