fix core to read ckeditor and handle hook-ins

This supports custom ckeditor plugins and a custom ckeditor config
and reads $eventData for
- normal entry form (case1) textareas,
- staticpage (case2) textareas and
- other nugget plugins (case3) textareas.
They all are build differently, therfore we needed three cases.
Please test!

Based to following commits
 8e26bd9 prepare core ckeditor for custom config and plugins
 44ea050 fix virtual js
 40609d8 add backend_footer hook

References #72