Support CLUSTER SLOTS command

* CLUSTER SLOTS returns a Redis-formatted mapping from slot ranges to IP/Port pairs serving that slot range
* description link including output format
** e14829de30
* Unit test included

src/main/java/redis/clients/jedis/Client.java

@@ -1011,4 +1011,8 @@ public void clusterSetSlotStable(final int slot) {
     public void clusterFailover() {
 	cluster(Protocol.CLUSTER_FAILOVER);
     }
+    
+    public void clusterSlots() {
+	cluster(Protocol.CLUSTER_SLOTS);
+    }
 }