bypass amazon lbs for websocket

Amazon LBS does not support websockets and strips off `Upgrade: websocket` headers from requests that it forwards. Forcing a `101 Switching Protocols` response makes it drop the connection.

This PR makes JuliaBox point the websocket URL to the public address of the ec2 instance hosting the user's session. So while the rest of the pages go through the load balancer (doing this lets javascript access the DOM of all embedded frames), websocket requests go to the ec2 instance directly. This also required a switch ipython to `3.0.0-dev`, and it currently uses a fork till ipython v3 is out.

Also included are changes to backup all contents from user home (including dot files/folders) except those that may interfere with stability of JuliaBox.