Add django_nose to apps only when testing

In base.py, only add django_nose to INSTALLED_APPS if 'test' is
in sys.argv, which seems like the simplest way to only load it
when running a test. (We don't install django_nose in production
anymore, so need it not to be in INSTALLED_APPS otherwise.)
Merge pull request #70 from dpoirier/fix-deploy-error

Move nose configuration out of base settings