Workaround to stop problem running setup.py test

multiprocessing and logging don't get on with each other in Python vesion 2.7.3 (but is fixed in 2.7.4). Importing multiprocessing in setup.py is a workaround mentioned in a couple of places online.

See: http://bugs.python.org/issue15881#msg170215
Merge pull request #23 from alphagov/multiprocessing-AttributeError-workaround

Workaround to stop problem running setup.py test