Mention Window::addIdleCallback in Application::addIdleCallback

Signed-off-by: falkTX <falktx@falktx.com>

dgl/Application.hpp

@@ -79,7 +79,7 @@ public:
       Add a callback function to be triggered on every idle cycle.
       You can add more than one, and remove them at anytime with removeIdleCallback().
       Idle callbacks trigger right after OS event handling and Window idle events (within the same cycle).
-      There are no guarantees in terms of timing.
+      There are no guarantees in terms of timing, use Window::addIdleCallback for time-relative callbacks.
     */
     void addIdleCallback(IdleCallback* callback);
 

dgl/Window.hpp

@@ -458,15 +458,4 @@ private:
 
 END_NAMESPACE_DGL
 
-/* TODO
- * add eventcrossing/enter-leave event
- */
-#if 0
-protected:
-    bool handlePluginKeyboard(const bool press, const uint key);
-    bool handlePluginSpecial(const bool press, const Key key);
-#endif
-
-// -----------------------------------------------------------------------
-
 #endif // DGL_WINDOW_HPP_INCLUDED