Forces use of polyfill in IE 11 since IE 11's native one causes XML data issues
npm install mutationobserver-polyfillrequire('mutationobserver-polyfill')
Uses latest release of MutationObserver polyfill from
https://github.com/webcomponents/webcomponentsjs.
If the environment isn't a browser, exists silently.
npm start
Pulls latest MutationObserver polyfill from webcomponentsjs