Bug 1036486 less2stylus

See https://bugzilla.mozilla.org/show_bug.cgi?id=1035783

[staticfiles](https://github.com/mozilla/olympia/pull/110) PR needs to be landed before.
this syntax of stylus is completely unreadable IMO.

I would suggesting looking at these conversion tools:
https://gist.github.com/cvan/5061790
https://gist.github.com/astronaughts/4618383
https://gist.github.com/RobertWHurst/5690400