Apply Sentinel runtime configuration API introduced on Redis 2.8.4

* Implements new sentinel commands (failover, monitor, remove, set) 
* unit test included
** added 2 redis-server and 1 sentinel for failover test
* with some refactoring
** SentinelCommands : refactor to have interface
** HostAndPortUtil : same format to cluster setup

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

@@ -0,0 +1,22 @@
+package redis.clients.jedis;
+
+import java.util.List;
+import java.util.Map;
+
+public interface SentinelCommands {
+	public List<Map<String, String>> sentinelMasters();
+	
+	public List<String> sentinelGetMasterAddrByName(String masterName);
+	
+	public Long sentinelReset(String pattern);
+	
+	public List<Map<String, String>> sentinelSlaves(String masterName);
+	
+	public String sentinelFailover(String masterName);
+	
+	public String sentinelMonitor(String masterName, String ip, int port, int quorum);
+	
+	public String sentinelRemove(String masterName);
+	
+	public String sentinelSet(String masterName, Map<String, String> parameterMap);
+}