Switch to a redis implementation that can handle multiple instances
Merge pull request #253 from dstufft/refactor-redis

Switch to a redis implementation that can handle multiple instances
Add support for user sessions
Add a basic framework to handle user authentication
Add the start of a template and CSS work for a login form
Implement CSRF
Move the classes to the top of warehouse.sessions
Remove note about nonlocal, we've switched to Python 3.4
Rework the session handling to use a dispatch_view decorator
Store our sessions inside of redis using msgpack to serialize
Move the session cycling support to our RedisSessionStore
Move our random token support into warehouse.utils
Use warehouse.utils.random_token for our CSRF tokens
Make the max age for the RedisSessionStore default to 3 hours