Default device lists default to CAM device name.
Simplify, correct and make more complete CAM support.
With the above we can finally use libcdio for cd-read, vcdimager and
probably vlc and xine.
Many thanks to Heiner.
Hopefully 3 bugs are fixed:
- we get the leadout track now, no core dumps
- MSF reporting is corrected
- track format and mode
_cdio_linux.c: use cdio #define rather than GNU/Linux one.
