Second stage of simplification - divider group property is an item, simplifying the anchoring of the contentItem. PropertyChange does not backup the property binding, uses QQmlPropertyPrivate::write() with parameter to keep bindings. ListItemAnimator uses behavior to animate snapping. Styling got "styledItem" context property to obey general styling rules. clicked() and pressAndHold() emission fix when content is swiped.
Approved by Tim Peeters, PS Jenkins bot.