tagging new resources works, incl. autocompletion and ref'ing existing tags.

- introduced client-side singleton like AppModel
- extended model about "Published" flag for resources (set true per default)
- switched ckeditor iback to div-inline ck-editing mode
- tested uploading images with div-inline ck-editing mode

Pending: mathjax-rendering to be fixed.

Note: You must reset your DB.