I'm not completely sure what the best strategy is in this case. Ultimately, it's good
that the format itself carries the block dimensions. It makes a lot of the code somewhat
uglier though, but really the only thing that we're sullying is the succinct ability to
determine what large-scale format it's in (PVRTC vs ASTC instead of 2bpp PVRTC vs 4bpp).
Fixed the notion that the CEM data was right after the first six bits
after the partition mode. It's actually right before the texel weight
data. Still not sure whether or not the texel weights are read in
the opposite order from the color data...
Also, added some preliminary integer sequence decoding. This will need
to be tested before we actually figure out if we did it correctly or not...
