Added robots.txt.
Ignore /tmp.
Replaced index with a Markdown version (which renders identically).
Got rid of the intermediate template.

Since I used to have both Markdown and HTML files (for legacy reason),
there was a common root-template, and a sub-template for markdown files.
All pages are not Markdown files, so the templates have been merged into
a single one, and the build process updated to reflect that.
Minor LESS fixes.

The font-face was not being imported anywhere, so systems without Open
Sans or Actor would not render properly.
The subtitle for the header received some font-face love as well.