Priority support for MongoDB transport. Transport table update. Priority
conversion unification.
Be selective about how file descriptors are removed since they may be reused for a different purpose.

Kombu was removing them after they were being reused by another worker process.
Adds Roger Hu to AUTHORS
master now depends on Python 2.7
Using print function
parse_url function should not know about mongodb, and the transport already sets can_parse_url
flakes
Adds sanitize_url and as_url to kombu.utils.url
Adds maybe_sanitize_url to kombu.utils.url
Tests passing
Merge branch 'daevaorn/priority'
Removes anyjson dependency :sad:
Removes importlib depdendency in bdist_rpm
flakes
kombu.five now extends amqp.five
Removes kombu.utils.compat.get_errno
Tests passing on Py3
Adds CI for Py3.4
sanitize_url now works if host is None
Fixes typo in comment