Proof names

[clayrat]

For now I've been simply converting snake_case to camelCase in proof names, but I think once Bip proofs are done, we should go through them and rename to reflect the names of actual Bip functions (e.g., subMask* -> bimMinus* etc).

[sbp]

Agreed, and I was thinking about renaming some of the functions anyway. My plan was to go through the Idris libraries looking at existing arithmetic functions to see how they're named, and then to copy that style as much as possible in this library. Since this is Idris, it'd be better to be consistent with Idris rather than with Coq. In any case the existing naming is not very consistent—e.g. I'm using things like "DMO" to abbreviate "doubleMinusOne", whereas there's also "pred" for predecessor to express minus one in other cases.