added option to force the enemies layer to always be enabled with floor music

-fixed wrong track type sometimes being used by the 'use floor music setting

-fixed per-track shuffle lists in custom soundtracks being capped by the number of soundtracks enabled for regular shuffle
-fixed variant type not updating when a soundtrack is shuffled (e.g. you can have supermeatboy soundtrack on while in an arcade and hit the shuffle button to change which arcade track is playing)

fixed 'floor music' setting for tracks in custom mode using its own soundtrack selection instead of using the floors soundtrack

fixed antibirth secret room song loop

fixed shop floor in greed mode continuing the fight music after ending a non-boss wave (when used with repentogon)

added extra backup check just in case music queuing is somehow messed with during the run start jingle

added extra checks to a StageAPI workaround function

moved extra custom soundtrack stuff to a separate mod so there won't be conflicts/overwriting from mod updates (and makes it a bit simpler)

fixed AB+ code trying to reference something that only exists in repentance