Some cleanup and allowing people to expose lists and hashes

Did a bunch of cleanup of core.py to address Issue #88.  Then cleaned up some other bits that you may or may not want.

Pinning to a specific older pyzmq version was needed because of gevent_zmq.py.  Replacing that with zmq.green removed that requirement (Issue #77) though you may decide you still want to pin to a specific version.  It looks like there maybe a slight performance reason to use gevent_zmq over zmq.green (Issue #73, #60) but I haven't had time to confirm that.  I'd also point out that the ability to unpin the pyzmq library may allow using the [new](https://raw.github.com/zeromq/zeromq4-x/master/NEWS) ZeroMQ [security features](http://hintjens.com/blog:49) as a(nother?) way to address authentication (Issue #46)