Update zmq.hpp
Update zmq.hpp

work in progress...
added monitor_t class
added monitor() method
michele-brambilla/ConfigurationService,michele-brambilla/ConfigurationService,jens-auer/cppzmq,virtdb/cppzmq,K0n63n/cppzmq,eburkitt/cppzmq,caidongyun/cppzmq,zeromq/cppzmq,bsn069/cppzmq,chenwenbin928/cppzmq,zeromq/cppzmq,michele-brambilla/ConfigurationService,cmcmurrough/cppzmq,michele-brambilla/ConfigurationService,michele-brambilla/ConfigurationService