Now that the Object class implements parent-child relationships, make it possible to create EventNotifier and Timer instances with a parent by adding a parent argument to their constructors. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>