Cryptol 2.3-alpha couldn't math, but thanks to @yav's hard work, Cryptol 2.3 and
later can math! So with our new found powers comes great simplification. Not
all is perfect, much like Dori-Mic's situation, but things are much better.
See the width constraints in SCrypt.cry for areas that could be improved with
some semi-obvious statements (forall x. 1 + width x >= width (x - 1)).
