We now force ForwardingCacheBackend as the default cache backend, and

instead work with the 'forwarded_backend' cache name when looking up or

saving the real cache backend.
This covers the configuration forms, cache stats, and initial settings

population.

Successfully loaded my cache settings.
Switched caches in the UI and reloaded the stats page. Saw that it

immediately updated for the current cache settings.
Started up memcached in verbose mode. Switched from local memory caching

to memcached and immediately saw operations on memcached.