Using mold-source-maps to remove working path from source map

It still shows up in the sourceURL embedded by a traceur compiler. Still
need to work on that, but this is a little better.
Merging some shared styles
Condensing some styles
Changing how permalink and download links are hidden

Using a class name instead of setting the display CSS property. This
way, the ::after of the download link can be hidden when the permalink
is gone
Preventing unnecessary logging when running tests