Log Message:
Import gts-0.7.6 as wip/gts.

This is the GTS library. GTS stands for the GNU Triangulated
Surface Library. It includes a number of useful functions to deal with
triangulated surfaces including, but not limited to, multi-resolution
models, Delaunay and Constrained Delaunay triangulations, set operations on
surfaces (intersection, union etc ...), bounding-boxes trees for efficient
collision and intersection detection, triangle strips generation for fast
rendering.