Namespace collision with CKEditor Notification plugin

[quintusl]

Using HTML5-Desktop-Notifications, babel-polyfill and CKEditor Notification plugin. There is a class name collision and it turns out having error

Uncaught TypeError: w.external.msIsSiteMode is not a function

The issue is encountered on Firefox 53.0/macOS, Chrome 58.0.3029.96/macOS. Either renaming CKEditor's notification plugin class or HTML5-Desktop-Notifications class name will workaround the issue.