* Replace css-escape-polyfill.js with escapecss.js utility module
* Add $tw.utils.escapeCSS() method and invoke that function within the
escapecss operator.
* Add test cases for the "escapecss" filter operator
* Fix $tw.boot.doesTaskMatchPlatform() so it works as expected if
a module's export.platforms contains more than one values
* Add missed files to the last commit
