addongui: fix fallback method if addon does not provice a skin file for current skin
dvdplayer: reevaluate HasVideo/Audio after a stream change
LinuxRendererGL: trigger reset of scaling when entering/leaving fullscreen video
VideoRenderer: add gui setting for threshold when hq scaling is desired
only free unused textures after a flip
RenderManager: squash to skip very late frames
AE: some Opening fixes