Regarding tilemap and attrmap encoding

[Rangi42]

• peach.tilemap and peach.attrmap are committed, but none of the other decoded files are; should they be?
• Running convert_background.py decode on menu_file_selection.tilemap.encoded and menu_file_selection.attrmap.encoded fails with an IndexError. I think this is because they fallthrough into the subsequent tilemap03 data. It might be more useful to combine those files, and instead of the Tilemap03 and Attrmap03 pointers, store either a raw address (like the ._07 dw $D651) or an offset from the base pointer (e.g. dw MenuFileSelectionAttrmap + $0123).
• Tilemap06 and Tilemap09 might also belong combined with another file. This would explain why some decoded files fail to open in Tilemap Studio, e.g. inventory.tilemap complains "Attrmap is longer than tilemap."

[kemenaran]

Indeed, the decoded tilemaps and attrmaps are there by mistake, and should not have been included in the project. I opened #346 to remove them.

As for the combined/fallthrough tilemaps, merging them and storing them as an offset from a base pointer would definitely be a good idea, yes.