Add some tests

[coleshaw]

I would recommend adding some sort of test suite to the app. For things like canvas, Webcam, or audio record methods, you can probably mock out the APIs or use sinon to make sure that the right methods are called (i.e. that this.video.pause() is called for the hideVideo method).

You've already broken stuff up really nicely into separate methods, so I would just say that tests for the important ones (ideally all) would help make sure the app is robust and probably catch some corner cases.