Address 'constant-time' TODOs in field impls
Merge pull request #92

137e77a Address 'constant-time' TODOs in field impls (Peter Dettman)
Fix typo
Label variable-time functions correctly and don't use those in sign
Merge pull request #94

da55986 Label variable-time functions correctly and don't use those in sign (Pieter Wuille)
Implementations for scalar without data-dependent branches.
Misc. Warning and cosmetic error cleanups.

This fixes a cosmetic precedence bug in the tests along with some
 type warnings.

It also adds a dummy cast to the CHECK macro to avoid hundreds
 of statement with no effect warnings on compilers that warn about
 such things.
Remove some dead variables in the tests.
Merge pull request #77

1d52a8b Implementations for scalar without data-dependent branches. (Pieter Wuille)
Merge pull request #95

79ad6d4 Remove some dead variables in the tests. (Gregory Maxwell)
9974d86 Misc. Warning and cosmetic error cleanups. (Gregory Maxwell)
Rewrite mul/sqr for 32bit/64bit

- interleave calculation of the lower and upper partial product ranges, and reduction
- less registers needed, more opportunities for parallel ops