Implement the SP_SetText* and MultiSprite_* functions added by
StoatSpriteEngine (as well as the TRANS_* functions introduced in
SACTDX). Enough to get to the opening movie in Vanish!
Split the code from sact_graphics.c into sprite.c and hll/SACT2.c.
sprite.c contains an index-independent sprite/scene interface, whereas
hll/SACT2.c handles the indexing of sprites.
This is to better support the StoatSpriteEngine.MultiSprite_* functions,
which use a different indexing system.
- Create separate directories for source and header files.
- Build code shared between xsystem4 and aindump as a static library.
- Create header dirs gfx/ system4/ and vm/
- Make CG.c/h usable without a running VM