Changes:
* moved waiting for synced caches before starting any work
* refactored worker() to really quit on quit
* changed queue to a ratelimiting queue and added retries on errors
* deep-copy deployments before mutating - we still need to deep-copy
replica sets and pods
* rolling.go (has all the logic for rolling deployments)
* recreate.go (has all the logic for recreate deployments)
* sync.go (has all the logic for getting and scaling replica sets)
* rollback.go (has all the logic for rolling back a deployment)
* util.go (contains all the utilities used throughout the controller)
Leave back at deployment_controller.go all the necessary bits for
creating, setting up, and running the controller loop.
Also add package documentation.
