Initial IE 11 support. Add babel polyfill. Fix a small event error.

ui/src/index.js

@@ -1,3 +1,5 @@
+import 'babel-polyfill'
+
 import React from 'react'
 import {render} from 'react-dom'
 import {Provider} from 'react-redux'

ui/src/shared/middleware/resizeLayout.js

@@ -7,7 +7,9 @@ export default function resizeLayout() {
       action.type === 'ENABLE_PRESENTATION_MODE' ||
       action.type === 'DISABLE_PRESENTATION_MODE'
     ) {
-      window.dispatchEvent(new Event('resize'))
+      const evt = document.createEvent('HTMLEvents')
+      evt.initEvent('resize', false, true)
+      window.dispatchEvent(evt)
     }
   }
 }