/*
 *  call-seq:
 *     Screen.close
 *
 *  Close the Screen, making the Rubygame window disappear.
 *  This method also exits from fullscreen mode, if needed.
 *
 *  After calling this method, you should discard any references
 *  to the old Screen surface, as it is no longer valid, even
 *  if you call Screen.new again.
 *
 *  (Note: You do not need to close the Screen to change its size
 *  or flags, you can simply call Screen.new while already open.)
 *
 */
VALUE rbgm_screen_close(VALUE module)
{
        SDL_QuitSubSystem(SDL_INIT_VIDEO);
        return Qnil;
}