Plug Websockets
Add {get,set}CallStatus on the storage
Add a pubsub mechanism
Add sockets, WIP
Following WIP
Added comments, finished the state machine implementation
Add some comments
WIP
handleHello test with token and hawkId authentication.
Add test for broadcast.
WIP Race condition with updateCallState.
Handle Race condition with Redis sets
Add tests
Start implementing tests.
Ensure state is valid when storing it
Remove trailing spaces.
Improve the socket protocol:

- Better handling of errors;
- Proxifying of the termination reason;
- Check that reason is alphanumeric.
Handle supervisoryTimer events.

r=@natim
Add ringing and connecting timers.
Merge master.