* Some fixes for the new GLRenderer
Changelog:
- Fix transparency of the window on some games on Windows.
- Fix escape key not being able to exit emulation.
- Fix inverted logic in fullscreen event handling.
- Fix a race condition when stoping emulation causing a hang.
- Fix a memory leak of the OpenGL context when stoping emulation (saving ~200MB of RAM when stoping emulation).
- Simplify and document behaviours when exiting the emulator while the
emulation is running.
* Make sure to clear alpha channel when presenting Texture
This fix once and for all the transparency issue on Windows.
* Enforce footer bar size to avoid gl widget to get resized to 1280x724
* Fix full screen inversion in MainWindow and make sure _listStatusBox don't come back when not needed
* Remove previous transparency clear attempt that is useless now
* Remove an extra line return
