Route SDL palette changes through SDL_SetPalette()

This is apparently the correct way to do things, since SDL wants to
know when the palette changes in order to recalculate certain
internal things. We should probably also add a setMany() method or
something on PaletteInterface to do this efficiently.
 # Please enter the commit message for your changes. Lines starting
Remove rdfull.but

This results in a significant reduction of BigHardMe(), but it still
also looks at LIFTOFF.ABZ, which hasn't been PNGified yet. Sigh.

Incidentally, this also closes #107.
Take a stab at decoding liftoff.abz

SVC0 is messed up and I don't know why. The rest of them seem okay.
Replace liftoff.abz usage in BigHardMe()

This function is now legible, and we're free to wonder why it gets
purchased items from one set of files with one naming scheme and
not-yet-purchased items from another set of files with another
naming scheme. And hey, now we can fix it!