Fix bug in "_setupRegularCleanup()" where the interval callback was trying to access an object that has been garbage-collected in the meantime.
Models attached to a KeyValue connector get the following *static* methods: Color.set(key, value); Color.set(key, value, ttl); Color.set(key, value, { ttl: ttl }); Color.get(key); Color.expire(key, ttl);