implemented bitcount and bitop commands for Redis 2.6

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

@@ -190,4 +190,11 @@ public interface JedisCommands {
     Long lpushx(String key, String string);
     
     Long rpushx(String key, String string); 
+
+    Long bitcount(final String key);
+
+    Long bitcount(final String key, long start, long end);
+
+    Long bitop(BitOP op, final String destKey, String... srcKeys);
+
 }