Separate the library and binary sources.

This is because binaries are about to be more than one source file, so
it'd be nice to have a more significant division than "this one has
'main' in the name."
Factor out first-specific CIF TREE stuff.

For incoming multi-game-ness.
Have the CIF tree extractor accept a game number.

Far from the best way to do it, waiting on me finding a suitable
solution for commandline processing. Also fixed up the "is this really
the first game" checker to actually be false sometimes.
Process CIF TREEs from Game 2's format.
Update docs on Game 2's CIFTREE format.
Implement decompression check, TGA making for game 2 CIF TREE.

Still need to implement a CIFLIST parser, because game 2's file types
don't correlate with what type of file they get categorized as, like in
game 1.