Fix #337 -- component importance.

If a matching component and the corresponding token are both important, treat it as if neither is
Version 2.2.13.
Add roundingPrecision to programattic description
Merge pull request #340 from lukeapage/patch-2

Add roundingPrecision to programattic description
simplifies transparency check to only look for zeroes in all parameters. fixes overeager transparent keyword optimization
Finalise repository move.
Fixes #342 - using clean-css in gulp via vinyl-map wrapper.
Makes multival operations idempotent.
Fixes #341 - ensures output is shorter than input.

* Was not the case for multival expressions (e.g. multiple backgrounds).
Fixes #339 - skips invalid properties.

* Skips processing of properties without values.
* Passing selector name to property optimiser is far from ideal but have to do for the time being.
Version 2.2.14.
Merge pull request #343 from noslouch/master

Simplifies transparency check to only look for zeroes in all parameters.
Updates release notes.
Allows `target` option to be a path to a folder instead of a file.

* Should fix #336.
* For examples regarding root / target / relativeTo take a look at https://github.com/jakubpawlowicz/clean-css/blob/master/test/unit-test.js#L971 - 'urls rewriting - root and target' test.
Make use of node-js' `os`.