Fake memcached endpoint speaking the classic memcached text protocol.
Bucketless, so it uses the bucketless side of FakeRiak.SimpleStore.
Supported commands: get/gets, set/add/replace/append/prepend, delete,
version, quit.
Note: this is a fake — the flags and exptime a client sends on set are
accepted but not persisted, so get always reports flags of 0 and keys
never expire. Only the raw value bytes are stored. The CAS value reported by
gets is synthesized from a hash of the value (it changes when the value
does, but distinct stores of equal values share it), and the cas command
itself is not implemented.