[2.1.0] 2018-09-23

Added

• Add function to LocationGraphNode to assign a "color" to each leaf node (in the form of an Int value) such that the resulting triangulation is 4-colored: no two triangles adjacent on a common edge have the same color.
• New unit tests for delaunay triangulation.

Fixed

• Various debugging improvements for Delaunay triangulation, like how edges and triangles created due to edge flips are named, and test Swift generation for Triangles.