Research alternate WebGL wrappers

[thoughtspile]

Three is a fat dependency with many features we don't need. Some candidates would be:

• https://github.com/regl-project/regl
• https://github.com/oframe/ogl
• https://github.com/greggman/twgl.js
• https://github.com/vaneenige/phenomenon
• https://github.com/evanw/lightgl.js