GUI init

gistfile1.java

        NiftyJmeDisplay niftyDisplay = new NiftyJmeDisplay(assetManager,
                                                           inputManager,
                                                           audioRenderer,
                                                           guiViewPort);
        nifty = niftyDisplay.getNifty();
        nifty.registerScreenController(mainMenuState);
        nifty.registerScreenController(loginState);
        //nifty.fromXml("Interface/GameGUI.xml", "MainMenu");