Now with GNU MultiPrecision (GMP) integers

gmpint.h is (in theory) mostly inline and shouldn't add much overhead
and was simpler than trying to understand the C++ "binding".

The Str() function is kind of terrible but that can't be helped.

Also fixed bug in realops tester (even the testers have bugs...)
And removed asm tester because the asm function is gone.

The bezier testers now don't compile, I don't think we need them anymore.