a m3u 'file' which it feeds to the m3u demuxer.
  Problems: - it requires a dir to end with /
            - if i enabled it, all files would use the m3u demuxer for some
            strange reason. i've spent a day hunting this down, reboot-
            strapping and doing who knows what. I'm sick of it now.
            Someone else can give it a try, if he wants to.