Loom sound fixes
This is an attempt to fix two slight sound problems in Loom.
The first problem is that the sound doesn't stop if, for instance, I hit Escape to skip a cutscene. In these cases Loom will try to play a sound with offset and delay both being 0. Applying this part of the fix shouldn't break anything else, since it's within a Loom-specific piece of code.
The second problem is that during the final confrontation with Chaos, Loom will cause stopSound(0) to be called. Since current_cd_sound is 0 at this time, this will cause the CD (or MP3) to stop. I don't think Loom ever does anything that causes current_cd_sound to be set, and anyway 0 is used to indicate that there is no current CD sound. This part of the fix, I'm less certain about.
Ticket imported from: #594921. Ticket imported from: patches/114.