Merge pull request #2 from amyangfei/develop

minor update
complete majordomo protocol.

work can be finished by peer broker's worker successfully.
TODO: a bug about work statistics, receive work message back in wrong sequence. related to message lost, however receive message back as DEALER's asynchronous feature.

Thread ID: 4480049152 [ERROR] mdp_client.c:228 mdp_client_timeout_recv() client-2 E: CLIENT EXIT - lost task DAE8
task_id------recv_back
9A54------DAE8
8924------9A54
027C------8924
A642------027C