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.

You mean without the braces, semi-colon, etc. If yes, this is a deliberate choice we made on purpose, because we find this more comfortable to work with ;)
YMMV :)