Created a simple chat client using zmq REP/RES and PUB/SUB.  I feel like there is probably a better way to do this as REP/REQ needs to send a response for each request.  That means I send out a "fake response" before I use the publisher socket to broadcast messages.  I would rather not send that extra message.  Oh well, this is really my first attempt to create a chat system ever so I am alright with the simple results.

 It is not even remotely robust, but it was really just to examine more how sockets and responses work with Node and ZMQ.  This is not from the book.