Move editor.contents to editor.ui.contentsElement.
Docs.
Create notification element using js instead of HTML.
Small changes in _layout.
Close notification automatically after duration.
Refactoring. Separated notification and notification area. DOM elements are now create in the constructors.
Update docs after refactoring.
Use CKEDITOR.plugins.notification instead of CKEDITOR.plugins.notification.notification.
Introduced notification_duration config.
Tests: in progress...