Include signalling for detecting abrupt disconnection etc

[mo3rfan]

Either:

Implement an ice connection state handler

Against

• https://bugs.chromium.org/p/webrtc/issues/detail?id=1676#c12

For

• https://stackoverflow.com/a/35584997/679829
• https://groups.google.com/forum/#!topic/discuss-webrtc/zgyJ89d0Z3A

Include some sort of polling over the data channel.