Convert slides to markdown

[larsks]

I've converted the slides from html to markdown using pandoc and the magic
of manual editing. The slides are loaded from slides.md by index.html.
I believe this makes both the prose and code examples easier to edit.

I have reproduced the navigation structure of the original slides.

[larsks]

Hey, apologies for the unsolicited re-architecture of the docs. I was thinking about updating some of the code samples, but when I realized that meant editing code in an HTML document I was sad.

I'm pretty sure the markdown version renders identically to the html version, with the exception of the definitions (which are now a <ul> because there isn't standard markdown support for definition lists).

[codecov]

Codecov Report

Merging #49 (b08e810) into master (7c42020) will not change coverage.
The diff coverage is n/a.

❗ Current head b08e810 differs from pull request most recent head 2d10d97. Consider uploading reports for the commit 2d10d97 to get more accurate results

@@           Coverage Diff           @@
##           master      #49   +/-   ##
=======================================
  Coverage   49.83%   49.83%           
=======================================
  Files          66       66           
  Lines        3921     3921           
=======================================
  Hits         1954     1954           
  Misses       1752     1752           
  Partials      215      215           

[stv0g]

Hi @larsks,

thanks for restructuring the docs :) I've done another pass at making them easier to read by harmonizing indentation and removing some for the cryptic abbreviations.