[web/view/treeview] add a 'selected' class on <li> if the entity's url is the currently displayed url An alternative would be to refactor the corresponding view so that controlling css classes wouldn't require overriding a 5O-lines method. Notice by default there is no associated class in the CSS so there is no rendering difference unless one explicitly add rule in his CSS file.

raise NotImplementedError("Cannot migrate such an old version. Use intermediate Cubiweb version (try 3.16.x)")