Add Babel Polyfill

Fixes some IE bugs, plus gives us a few more ES2015 features.

package.json

@@ -36,6 +36,7 @@
     "babel-plugin-react-require": "^3.0.0",
     "babel-preset-es2015": "^6.18.0",
     "babel-preset-react": "^6.16.0",
+    "babel-polyfill": "^6.20.0",
     "eslint": "^3.10.2",
     "eslint-config-airbnb": "^13.0.0",
     "eslint-loader": "^1.6.1",

webpack.config.js

@@ -6,7 +6,7 @@ const PATHS = {
 };
 
 module.exports = {
-  entry: "./js/main.js",
+  entry: ['babel-polyfill', './js/main.js'],
   output: {
     path: path.join(PATHS.dist, 'js'),
     publicPath: '/js/',