Support "/*!" syntax for @noflip

New feature in node-cssjanus v1.1.0.
Improve flipping of background-position

Fixed in node-cssjanus v1.1.0.

* Account for lack of vertical value in background-position.
* Preserve trailing zeros in background-position percentages.
Restrict four_notation_quantity to margin, padding and border-width

It previously applied to any property with 4 (or more!)
space-separated values. This was way too generic causing conflicts
with properties like border-radius. And caused unrelated
properties to get flipped.
Flip two values in border-radius rule (in addition to four values)

New feature in node-cssjanus v1.1.0.
Flip border-style

New feature in node-cssjanus v1.1.0.
Refactor test suite (use node-cssjanus v1.1.0 test data)

Source:
 https://github.com/cssjanus/cssjanus/raw/v1.1.0/test/data.json

Also set up Travis CI.
Add README
test: Set up phpcs (PSR-2 standard)
Set up Composer