Don't increase the semaphore is a callback is going to get called (this will make the callbacks waiting for the semaphore run for free, even there's no space to run them).
[Py3] Redis: Fixes fanout with pmessage on python 3.  Closes #324
Merge pull request #327 from celery/fix-async-sem-release

Don't increase the semaphore is a callback is going to get called
Semaphore tests
Bumps version to 3.0.14 and updates Changelog
Fixes tests on Python 3.3
Adds Trove classifier for Python 3.4
Adds Python 3.4 target for Tox
Adds Python 3.4 target for Travis CI
Travis does not support 3.4 yet
MongoDB: Fixes Python 3 compatibility problem.  Closes #328