Bugfix/memory leaks

A lot of view events were not being correctly unbound because of changes in Backbone meaning that events bound with `Collection#on` are not automatically unbound by `View#remove`

Switching these out for `View#listenTo` allows `View#remove` to unbind these, and the Views to be GC'ed.

Also explicitly remove child components of Graph views to allow for event unbinding in these.

![](http://media.giphy.com/media/374pcIBVEGb6g/giphy.gif)