th19: figure out what the new ANM fields are

[32th-System]

I assumed they were just the width and height of the entry's THTX block, but in front.anm, one entry uses the resolution from a different image. Right now, I see no correlation between those 2 variables and which image they correspond to, and I'm not sure if it's even used.

TODO:

1. Put these in the spec instead
2. actually figure out what these are
3. figure out if it's even used

[DankRank]

also gotta figure out what used to be the high byte of lowresscale, and the new fields in sprite_t

[DankRank]

high byte of lowresscale = jpeg quality