Added tox support to teat against Django 1.3 to 1.5 with Python 2.6 + 2.7.
check values returned by the cache layer against `None`, that avoid cache misses
incremented patch number
removed distribute from requirements.txt
Merge pull request #8 from revsys/bugfix/cache-fix

check values returned by the cache layer against `None`, that avoid cach...
fixed cache checking
invalidating cache is hard
version bump to 0.8.3