Visualizing 1Forms without using Arrows

Currently, there are two strategies for visualizing 1Forms on a spherical mesh.
1. Render the divergence of the 1Form.
2. Render the 1Form as a collection of arrows

We would like a better method wherein we visualize 1Forms as colored triangles. The color along an edge will be the color of the corresponding value in the EForm. Interior colors will be linearly interpolated.

This is similar to [Gouraud shading](https://en.m.wikipedia.org/wiki/Gouraud_shading) (except there, the values that inform interpolation are given at the vertices).