In this change router was redesigned in a way most
appropriate for routing concept of zmq.ROUTER socket.
DEALER(cli)-ROUTER(proxy)-DEALER(srv) instead of
DEALER-ROUTER-DEALER-ROUTER (3 layers instead of 4)
The main reason is to use zmq.DEALER identity in message
routing. For this reason DealerConsumer was introduced
server-side. RouterConsumer is left for peer-to-peer
DEALER-ROUTER deployment option.
Also handled assertions in receive-methods in order
to not stop server when received message with wrong format.
Change-Id: If25edf500fa8d220d4233bb13d67121824e841c6
Closes-Bug: #1558601
Related-Bug: #1555007
b5955b6ca9