Use Janus for video transport

[binarykitchen]

See http://janus.conf.meetecho.com/recordplaytest.html

Since it uses WebRTC, it should be a lot faster with it.

On the other hand, since it's written in C++, we'll need some interface/bindings between. But that is not too bad, see http://www.benfarrell.com/2013/01/03/c-and-node-js-an-unholy-combination-but-oh-so-right/