Use a different queue system

[François Marier]

Once we move our target platform to Debian wheezy, we should revisit the queue system we use (currently Gearman).

Ideally, we should use celery to interface with the queue:

  http://www.celeryproject.org/
  https://blog.serverdensity.com/using-celery-for-queuing-requests/
  https://speakerdeck.com/gchandrasa/an-introduction-to-celery

The underlying queuing system could be 0mq:

  http://pyfunc.blogspot.com/2012/03/introducing-mq-and-pyzmq-through.html