Ontology and Classification editor: add documentation
Classification graphs: refactor init of new graph
Classification editor: make sure root node forms offer roots only once
Classification editor: show a graph's root node name if available
 Classification editor: trim new class/relation names by default
Classification editor: make sure there is a project when refreshing
Classification editor: sort classes in dialog for new links
Classification editor: make string representation of links more human readable
Classification editor: allow non-owners of an element to edit/remove it