The problem with DVD/BD and playback resume is that most often, the
filename is just "dvd://", while the actual path to the DVD disk image
is given with --dvd-device. But playback resume works on the filename
only.
Add a pretty bad hack that includes the path to the disk image if the
filename starts with dvd://, and the same for BD respectively. (It's a
bad hack, but I want to go to bed, so here we go. I might revert or
improve it later, depending on user feedback.)
We have to cleanup the global variable mess around the dvd_device.
Ideally, this should go into MPOpts, but it isn't yet. Make the code
paths in mplayer.c take MPOpts anyway.