Various improvements, real pubsub unittest.

 * Set and forward zmq ioloop explicitly to ZMQStream.
   * tornado ioloop does not support ZMQStream as an file descriptor
   * makes clear where and how the loop is used / initialized
 * Add test for omnibus.compat
 * Removed coverage xml report
Merge branch 'master' of github.com:moccu/django-omnibus

Conflicts:
	tox.ini