AUTH support?

If I try
  val redisClient = RedisClient(endpoint)
  redisClient.auth("pwd")

I get an exception

```
at akka.pattern.AskableActorRef$.ask$extension(AskSupport.scala:136)
at com.redis.api.KeyOperations$class.auth(KeyOperations.scala:112)
at com.redis.api.RedisOps.auth(RedisOps.scala:7)
```
