Updated Mausoleum pits to the ones used in current Fiend Folio

Fixed missing assets

Integrated Rainbow Poop+ by dante to better fit the visuals of the Golden Poop, if this causes issues, please contact me and I will remove it

Fixed Dank Depths rocks and pits
Fixed Necropolis rocks and pits
Added custom assets for Caves

Added custom Boss Rush walls, spikes and pits. Assets are from Better Boss Rush Backdrop, I wrote the code though.