GuiScreenController: remove the {en/dis}ableSlider() methods

nifty/src/main/java/jme3utilities/nifty/GuiScreenController.java

@@ -76,30 +76,6 @@ public GuiScreenController(String screenId, String xmlAssetPath,
     // *************************************************************************
     // new methods exposed
 
-    /**
-     * Disable the named Nifty slider.
-     *
-     * @param name unique id prefix of the slider to disable (not null)
-     */
-    public void disableSlider(String name) {
-        Validate.nonNull(name, "name");
-
-        Slider slider = getSlider(name);
-        slider.disable();
-    }
-
-    /**
-     * Enable the named Nifty slider.
-     *
-     * @param name unique id prefix of the slider to enable (not null)
-     */
-    public void enableSlider(String name) {
-        Validate.nonNull(name, "name");
-
-        Slider slider = getSlider(name);
-        slider.enable();
-    }
-
     /**
      * Access the named Nifty button. This assumes a naming convention where the
      * Nifty id of every button ends with "Button".