title: Not able to receive chat messages using smackx MultiUserChat API
body: <p>I am trying to use smack API for Android to develop a chat room using gmail accounts. I managed to create a room and send messages to group. But when someone replies i am not able to receive incoming messages either directly on chat window or through program(muc.addMessageListener(myMessageListener) and PacketListener).</p>
  
  <pre>
  <code>
  
      ConnectionConfiguration config = new ConnectionConfiguration("talk.google.com", 5222, "gmail.com");
      config.setSASLAuthenticationEnabled(true);
      connection = new XMPPConnection(config);
      connection.connect();
      connection.login("kandroid6990@gmail.com", "password");
      muc = new MultiUserChat(connection, "private-chat-12325669-dead-beff-feed-fedcba987454@groupchat.google.com");
      muc.sendConfigurationForm(new Form(Form.TYPE_SUBMIT));
      muc.join("kandroid6990");
      muc.invite("karthikbaskar3@gmail.com/User1", "Welcome!");
      muc.invite("kamaraj6990@gmail.com/User2", "Welcome!");
  
  </code>
  <code>
  
      Message msg = new Message("private-chat-12325669-dead-beff-feed-fedcba987454@groupchat.google.com", Message.Type.groupchat);
      msg.addBody(Message.getDefaultLanguage(), messageText);
      muc.sendMessage(msg);
  
  </code>
  </pre>