Implemented BGSAVE

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

@@ -515,4 +515,8 @@ public class Client extends Connection {
     public void save() {
 	sendCommand("SAVE");
     }
+
+    public void bgsave() {
+	sendCommand("BGSAVE");
+    }
 }

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

@@ -607,4 +607,9 @@ public class Jedis {
 	client.save();
 	return client.getStatusCodeReply();
     }
+
+    public String bgsave() {
+	client.bgsave();
+	return client.getStatusCodeReply();
+    }
 }