Consider using websockets for GET requests

[joepio]

Since we have websockets anyway... It would be pretty simple to use these for GET requests. The performance should be at least a little better - there is not HTTP overhead, at least.

But how should we deal with errors? 404s and the like?

I think we need to reply with a valid Resource, with the requested @id, but we send an Error Resource containing a message. This is easy to render and handle in the front-end.