Deep edit links

To pull of deep edit links, I had to change from markdown2 to markdown. Luckily, this is something we've wanted to do anyway.

This prq gets rid of markdown2mathjax, so we should expect some regressions there until we can find/implement a replacement.

Closes #144 

## Missing:
- [x] Mathjax support
- [x] Wiki-tables replacement
- [x] Wrap sections in divs (@stianjensen is on this)
- [x] prettyprint