Renamed caching.base => caching.db
Added setting CACHEMACHINE_ENABLED
Fixed issue that can occur with exclude(), limits, and M2M fields with __in
Removing unused imports and variables
redis_backend: Fixes ImportError; `WatchError` => `redis.WatchError`
Fixes bug where caching manager expects a model's pk  to be 'id'
Sniffs OneToOne fields when caching.