Format code using 'cargo fmt'

[Atul9]

[cesarb]

Sorry, but formatting this code with rustfmt requires strategically-placed rustfmt_ignore annotations. Some of the constants in this code are 4x4 (or other size) matrices, and were manually formatted to make this clear. For instance, the shuffle matrices were formatted to make it clear what is being rotated, but this is obscured when they are placed as a single line.