Add new command: BITFIELD (Redis 3.2.0).

src/ClientInterface.php

@@ -46,6 +46,7 @@ use Predis\Profile\ProfileInterface;
  * @method int    append($key, $value)
  * @method int    bitcount($key, $start = null, $end = null)
  * @method int    bitop($operation, $destkey, $key)
+ * @method array  bitfield($key, ...)
  * @method int    decr($key)
  * @method int    decrby($key, $decrement)
  * @method string get($key)