Add missing CSS for octicon fonts that github half-embetted in the html.

This will allow for hidden inline links to various sections of the page
in combination with the next commit.
Add sexy hidden anchors.

Anchors will fade in and out on mouseover and are invisible otherwise.
Fix the alignment to make everything look pretty.

Adds a negative text indent to the octicon-link span to make text things
align correctly again. Looks nice. :)