change makefile to accept "start" and "stop" to be able to start the testing environment and stopping it for manual testing purposes.

raising down-after-milliseconds of sentinel 1 to avoid taking the master down and up all the time.
change sleep to 10 seconds after doing a "salveof" to avoid false negatives.

src/test/java/redis/clients/jedis/tests/JedisSentinelTest.java

@@ -25,7 +25,7 @@ public class JedisSentinelTest {
 	// TODO: The sleep is to give time to the slave to synchronize with the
 	// master and also let know the sentinels about this new topology. We
 	// should find a better way to do this.
-	Thread.sleep(5000);
+	Thread.sleep(10000);
     }
 
     @After