Log Message:
Update www/ruby-sass to 3.1.12.

3.1.12

* Compatibility with the mathn library (thanks to Thomas Walpole).
* Fix some infinite loops with mixins that were previously uncaught.
* Catch infinite @import loops.
* Fix a deprecation warning in sass --update and --watch (thanks to Marcel
  Köppen).
* Don’t make $important a special pre-initialized variable.
* Fix exponential parsing time of certain complex property values and
  selectors.
* Properly merge @media directives with comma-separated queries.
  E.g.

  	@media foo, bar { @media baz { ... } } now becomes
	@media foo and baz, bar and baz { ... }.