add LICENSE
rng: avoid recomputing a constant every time
update README.md
An implementation of the ray tracer from raytracing.github.io in Hare.
Everything from the first book is implemented. I intend to read through and implement the other two eventually as well.
The code prints out the output image to stdout in ppm format. You can convert it into something else with imagemagick or just pipe it directly into a viewer that knows about ppm.