[committed] add containsListener() and getListeners() to JoystickInput

MouseInput has these methods and they are useful. This patch adds em to JoystickInput too:



Index: src/com/jme/input/joystick/JoystickInput.java
===================================================================
--- src/com/jme/input/joystick/JoystickInput.java       (revision 4854)
+++ src/com/jme/input/joystick/JoystickInput.java       (working copy)
@@ -190,6 +190,23 @@
     }

     /**
+     * Check if a listener is already added to this JoystickInput
+     * @param listener listener to check for
+     * @return true if listener is contained in the listenerlist
+     */
+    public boolean containsListener( JoystickInputListener listener ) {
+        return listeners != null && listeners.contains( listener );
+    }
+
+    /**
+     * Get all added joystick listeners
+     * @return ArrayList of listeners added to this JoystickInput
+     */
+    public ArrayList<JoystickInputListener> getListeners() {
+        return listeners;
+    }
+
+    /**
      * @return number of attached game controllers
      */
     public abstract int getJoystickCount();

I guess it can't hurt to add those methods. I will commit the patch.

committed with r4862.