Polyfill issues with Babel 6

[bdowning]

Babel 6 is a bit of a mess. If I include the transform-runtime plugin with its internal polyfills, it winds up spewing out untranslated import statements into the webpack bundle. See discussion here:

https://phabricator.babeljs.io/T2877

Given that that issue is currently five months old I just hard-coded some polyfills so I could get it working in a browser faster. This should be fixed later when it can be.