Distributed test running

[moschlar]

Support to run a worker for running the tests on different nodes or only different users or security contexts.

Worker nodes should be able to "exist dynamically", e.g. dying of a worker node should not have a critical impact. Also, adding or removing workers at runtime should be easy. E.g. only start the worker script with an address/url and you're done.

Possible implementations could use:

• Celery
• Twisted Publish/Subscribe

PoC for Twisted from @danghvu: https://gist.github.com/danghvu/1d62e08854425d7b51eb