To build this you need:
* pandoc
* dejavu-sans and Arial fonts installed
  (the latter from msttcorefonts package or similar)
* xelatex with standard science article packages
  - easiest to get as MacTeX on Mac
  - `apt-get install -y texlive-recommended` on Ubuntu
* Stephen Diehl category theory diagrams:
  - git@github.com:sdiehl/cats.git
* markdown-unlit
* pandoc-hide-codeblocks