Exposed the models via the PolicyController.

Added: PolicyController and routes for the 3 required views.
Added: Additional 'expire' route to purge the entire cache.
Added: Seed file to fill database with 100 videos, for 6 countries, with random policies.
Changed: Models now encapsulate their own caching based on their primary key (only).
Fixed: A few caching bugs.
NOTE: Enabled caching on the dev environment: memcached must be running locally.