ZeroMQ Protocol Module

Create a ZeroMQ protocol module that extends event::handler and implements the ZeroMQ event loop using ScaleStack events. Provides an application API close the ZeroMQ API:
http://api.zeromq.org/2-1-1:zmq-cpp
The ScaleStack ZeroMQ API only supports non-blocking IO:
class socket_t
{
public:
  virtual void send_ready() = 0;
  virtual void recv_ready() = 0;
  bool send(message_t &msg_, int flags = ZMQ_NOBLOCK);
  bool recv(message_t *msg_, int flags = ZMQ_NOBLOCK);
  //...
};