WIP: Update to support CD version of Loom

Updated to rip CD audio instead of cdda.sou, which is not part of the original release of the game.

Two problems remain:

1. Steam/GOG packaging is likely broken, as they will not have any CD tracks to rip. Ideally, the package should allow EITHER the ripped CD audio OR cdda.sou.
2. The track number is 2 (per CD), but ScummVM expects the file to be called track1.ogg.

For the second issue, I was thinking a new parameter to rip_cd would be required, perhaps track_offset? Poking through the code, I'd just need to update build.py and data.py. Let me know if you think this is a good approach, or if there is a solution already that I'm missing.

For the first issue, I don't have any good ideas. I had a hackish thought of considering cdda.sou as a 'known_rip', but that will break the existing error checking. I know you guys have the 'alternatives:' grouping; can that be used in tandem with rip_cd? I guess the nuclear solution here is to just define two packages.