cavestory save lib

modify major values in CaveStory's profile.dat

You may want to check Fandom wiki for items.

Note

As impl From ... in src/items/*.rs, if you get invalid value from profile.dat, it will set to None(Nothing for BGM).

TODO

• flags (bitvec) - currently not in plan, as modify this may break game experience

lib.rs:

check profile.txt for value validation.