FFFF and 0000 -> prefer 0000
FFFF and 0001 -> prefer 0001
...
FFFF and FFFE -> prefer FFFF
they shouldn't be desync'd (incremental); only the uninitialized case is important to handle.
Increase abstraction for arbitrary slot get/set operations, and fracture
SAV4 behavior for each game type.
Adds: Undo/Redo of party slot changes
Fixes: Fixed Gen5 daycare slot 2 reading, and EXP reading
Fixes: Some slot color glitchiness
Fixed: Box layout editor now hides the flag label if no flags are
present
Fixed: Gen7 box flags are now shown (unknown purpose lol)
Changed: savefile objects are generally smaller (removed a few shared
offset fields)
