Use CSSJanus from upstream (v1.1.0)
Remove the local copy and include upstream instead.
Remove local unit tests as it's now a proper upstream lib that
is tested by uptream.
Release:
https://github.com/cssjanus/php-cssjanus/releases/tag/v1.1.0
Changes:
Features
* Support "/*!" syntax for @noflip.
* Flip border-style.
Bug fixes
* Improve flipping of background-position.
* Restrict four_notation_quantity to margin, padding and border-width.
* Flip two values in border-radius rule (in addition to four values).
Change-Id: Ieb6e179d6163f99a9c98fd99c2277d25135871fe