- Packages and groups check different fields for equality. - Selected-state is **not** part of equality. - Also operator !=
- Previously you would either need to know where in the tree a PackageTreeItem was, or guess that an empty packageName() means that it's a group.
- Just some simple tests for the Items - Test creation of package group from variant - This needs Qt5::Gui to link because QStandardItem is a GUI class, although we can run the tests without a GUI.