Updated 'MdgaServer' class.

Updated the 'MdgaServer' class by register the 'IncorrectRequestMessage' class to the serializer.

Projekte/mdga/client/src/main/java/pp/mdga/client/server/MdgaServer.java

@@ -135,6 +135,7 @@ private void initializeSerializables() {
         Serializer.registerClass(UpdateReadyMessage.class);
         Serializer.registerClass(UpdateTSKMessage.class);
         Serializer.registerClass(WaitPieceMessage.class);
+        Serializer.registerClass(IncorrectRequestMessage.class);
         Serializer.registerClass(Player.class);
         Serializer.registerClass(Statistic.class);
         Serializer.registerClass(Board.class);