Complete rewrite of Editors.

- Editors have been simplified by creating less scopes and are now better organized.
- For simple Editors that does not require any particular logic, there is now a way to automatically create the corresponding Directive with a single line of code.
- Breadcrumb can now be updated via a set of Directives: no need to create a Controller just to update the Breadcrumb, do it right in the template files!