Subscribing to notifications from SendorQueue will give updates on items as managed by the queue, instead of by the worker. This means for example that items are not removed when the worker is finished with them.
Introduced SockJS and Backsync for dynamically pushing updates server->client

Tasks, Targets & FileStash communicate entirely over a websocket now.
Targets & FileStash receive notifications whenever anything change in the backend, and the clientside Backbone model/view is updated to reflect this.

The Backsync library has been modified in a few places. The sample BackModel's on the Python side will require a few changes before they work again. The serverside signal mechanism has been commented out entirely.