Add an about page explaining the project
Finalize about page, add image
Change URL of about page -> /about.html

Since we can't control the web server serving this at GitHub Pages, we
can't setup proper URL rewriting to get rid of the extension. Ugly, but
keeps us from moving back to self-hosted site.
Add title and back arrows to about page
Merge pull request #5 from thusoy/aboutpage

Add an about page explaining the project