Patch requests.Response to be pickleable.
Fix tests. Require both request and response to cache.
Need both request and response internally to cache.
whitespace
implemented file and redis based caches.

These can only be used when lockfile and redis are available
respectively.
Removed redis cache example as it didn't work. Now included in cachecontrol.caches.RedisCache
Use pip install -e . in dev requirements.
Switching to invoke (http://pyinvoke.org) from paver.