In particular, use required properties where applicable, explicitly
import QtQml where we use it, avoid unqualified access into the root
scope of a component, use JavaScript functions with explicit parameters
as signal handlers.
Change-Id: I3eaaba47cc3c7a2a12d488e36f9eec145cedbb0e
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>