Fix validation rules for unique fields
Update callback for new documents and documentlists

Timestamp for created, creator and admins are now set correctly.
Remove unneeded attributes lastEditTimestamp and currentUserId
Fix two bugs in Document_list_mapper
Fix bugs in Document_model
Add action to publish a list
Fix spelling mistake in Document_list_mapper
Remove checking for status in function publish_list

Reason: Document_mapper::save doesn't return a status.