Ray Tracer Performance Improvements and STL files (opens in new tab)

I claimed last week that I'd have to put aside the fun I was having working through the Ray Tracer Challenge book in OCaml due to other commitments. And technically that was true, I didn't get to do any new features based on the book, I had a couple of longish train trips, and so I did go off piste a little and scratch a couple of itches with my ray tracer.