portal 1
========
- Register root handler
- Register skin
- Root handler, implement back-office view (STL, get_views)


portal2
========
- Add handler classes (get_document types, class_*)


portal3
========
- Add a front-office (Interface, App.get_interface)

portal4
========
- More of the same, nothing new.

portal5
========
- Datatypes and metadata.
