Investigate using core-js for polyfills

[zepumph]

Currently twice we have had to notice that sims stopped working IE, and then debug cryptic errors on that platform only to release that we need to polyfill (Promise for the webpack build, and Array.from).

I think we should investigate what it would look like to use core-js, as it seems to be the industry standard (babel-polyfill is deprecated in favor of it). Likely then we could get transpile.js and the babel core api to work with core-js (maybe with some tweaking)?

I'm not too sure, but it is worth investigation! I will take a look, and I will assign @jonathanolson and @samreid so they are aware. Please unassign if you don't want to or have the bandwidth to take this on right now. Whoever gets to it first go for it!