Optimized vapour.js Modernizr prefixing and now loading polyfill CSS

Also fixed IE9 parsing issue with the i18n base.js (coughed on //@TODO so added a space after //).

TODO: Find way to bundle polyfill JS as well as polyfill CSS so only download one JS file and one CSS file total for all required polyfills. That will need to be dealt with in a separate PR as this PR is intended to just get the CSS loading so polyfill work can continue.