MessageProcessor: Use raw zmq socket

makes transition to CurveZMQ easier

removes some cron and timeout functionality, will be re-added when required
> I think that it is not good idea to have separate thread only for timer. It is better to use event-driven reactor, use http://czmq.zeromq.org/manual:zloop or just zmq_poll.

That would be an even better solution, but takes more effort in my estimation. The looping separate thread could be implemented in less than two hours.