WebRTC data channels and/or arm flapping

A talk on using WebRTC data channels instead of web sockets for peer to peer data exchange, using my stupid game Flappy Arms as an example (basically, a distilled version of this post: http://blogging.alastair.is/webrtc-datachannels-or-how-i-learned-to-stop-worrying-and-flap-my-arms/)
Update index.html
clean up speakers
Merge branch 'alastaircoote-patch-2'