More cleanup. Added figures.

I brought in program.sty to help with the code snippets. I like it better than verbatim and listings because you can put arbitrary symbols in it and create references to particular lines, and it gives fine-grained control over tabbing, which makes it easier to line things up right. I moved larger code snippets and pictures into figures. Latex does a better job with placement, and captions can make things a bit easier to read. I put type names like Float32x4 into typewriter face throughout for clarity.

I would suggest putting the absolute timing results in the benchmark tables. I added red TODOs for that.