Additional fixes for Issue #41

Issue #41 was about an `zmq.core.error.ZMQError: Invalid argument` error when trying to connect to `tcp://*:4242`, however I ran into the same bug in Ubuntu 13.04 connecting to `tcp://:4242`.
Merge pull request #78 from jgeewax/patch-1

Additional fixes for Issue #41
Fixed deprecation warnings:
gevent.queue.Queue(0) now means infinity queue, changing to Channel instead.
gevent.coros module deprecated in favor of gevent.lock
replaced localtime example as it does not return a serializable response.
Made tests backward compatible with python 2.6 and fixed some more deprecation warnings
Merge pull request #80 from psantann/master

Fixed deprecation warnings & Update README example
Avoid using dict as default keyword argument
Merge pull request #83 from mahendra/cleanup

Avoid using dict as default keyword argument.

This is just for aesthetics, since those arguments are never modified in the code anyway (and unless I'm wrong, aren't modifiable outside of zerorpc's internal code) but you're right, it's good practice!
Using new style classes in code example.
Travis will now test against different versions of pyzmq.
Merge pull request #87 from thedrow/patch-3

Travis will now test against different versions of pyzmq.
Merge pull request #84 from thedrow/patch-1

Using new style classes in code example.