Only recompute if cost is below -FLT_EPSILON, we can get cases where both cases generate
very tiny negative costs (see 'Cylinder.004' mesh in .blend attached to report).
MSVC doesn't like caling macro argument f when using float values
in the macro, it simply replaces the f in the float value with the
argument..
CMake compilation still fails because of 77785ce708, numpy is never
getting unpacked.
Triangulate with beautify caused a bug when there were existing edges
could make the bmesh-operator return an invalid face-map.
Now the beauty is calculated on the 2d-tri's resulting from polyfill,
its simpler and faster.
