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

fixed bug with custom lua soundtracks setting a track to use the run start jingles or main menu music

added the ability to have additional custom soundtrack setups

tweaks to check for stageAPI messing with music in non-custom floors

added extra error check in continuous floor music function