Standardised module loading system & fixed build system

Fixed broken build system in broken webpack version.
Also updates module system to standardise on ES6 import/exports,
Especially since babel has changed it's 'default' logic for the old
module system.

resources/assets/js/vues/page-editor.js

@@ -145,6 +145,6 @@ let computed = {
     }
 };
 
-module.exports = {
+export default {
     mounted, data, methods, computed,
 };