This module will contain mirrored functions for calculating and applying
weights for points on a mesh. This includes barycentric and UV weighting
and possibly more advanced global weighting such as harmonic weights.
The naming should follow this scheme:
<type>_{2d,3d}_{calc,apply}
e.g.
poly_2d_calc
poly_2d_apply
uv_3d_calc
...
Reviewers: campbellbarton
Differential Revision: https://developer.blender.org/D939
