Update README to point to blog post

Correct some typos in README

Polish README

Improve scene description to be more interesting

Minor tweaks / formatting / style fixes

Add documentational comments to code

Final round of optimizations, tweak scene constants

Add better progress reporting with time estimate

Minor optimization for scattering on matte materials

Optimizations to path tracing code

Add depth-of-field blur (12)

Use shorthand for vec3 operations in lib/ functions

Add ability to adjust camera angle freely (11.2)

Camera refactor, customizable FOV (11.1)

Total internal reflection and partial reflectance (10.3 - 10.4)