Bezier curve related maths and tools.
This crate implement simple 2d quadratic and cubic bezier math, and an efficient flattening algorithm.
The flatteing algorithm implemented here is the most interesting part. It is based on: http://cis.usouthal.edu/~hain/general/Publications/Bezier/Bezier%20Offset%20Curves.pdf It produces a better approximations than the usual recursive subdivision approach (or in other words, it generates less points for a given tolerance threshold).