The old build system worked, but ssg adds some features while still
being simple and easy to hack on:
* set page title from the h1 tag, rather than the file name
* generate a sitemap (which we adapt to also generate a nav)
This site doesn't need a dynamic nav, but the Anarchy Planet docs site
will have a lot of rapidly changing pages and will benefit from a
dynamic nav. This way we can use the same build system for both
sites.
* add an empty footer
* add a minimal html header
* indent the nav
* modify the build process (publish.sh):
* use a tmp directory
* use discount markdown(1) rather than discount mkd2html(1)
* generate html page title from the file name
* indent html body
* use cat(1) to combine the pieces
* remove trailing newlines in publish.sh
* git ignore tmp/ directory
