OBJ

Support for Wavefront OBJ files

Triangles

Triangles (#51)

Fixes #50

Added triangle primitive, and some new benchmarks.

Bounding Boxes

Bounding Boxes (#49)

Fixes #48

Added axis-aligned bounding boxes.  Also
added some benchmarking functions and
posted their results in the readme.

Groups

Groups (#47)

Fixes #46

Added groups and reworked intersections
Updated to go 1.16

Cylinders and Cones

Factorion/issue43 (#45)

* Cylinders
Added cylinders, edited CI and README

* Cylinders
Fixes #43

Added cones and fixed cylinders.  Also pre-calculated transform inverses, it was a huge time-sink.

* Updated readme

* Update actions

Cubes

Cubes (#42)

Fixes #41

Added cubes, reworked testing to be their own package and require importing