dvdplayer: don't use OpenDefaultStreams() if something else dictate

This works for both dvd and bluray navigation
overlays: support ARGB image overlays
bluray: support still frames
bluray: support BDJ menus
dvdplayer: a disabled stream could be re-selected for bluray and dvd
dvdplayer: Always make sure first image after open is output

This solves some still frame issues with blurays
bluray: factor out overlay functions to reduce code duplication