The main motivation for this is convenience, but it also allows controls
to respond to resizing for items that have animations without resorting
to JavaScript to call restart().
[ChangeLog][QtQuick] It is now possible to set the from, to, duration,
and easing properties of a top-level animation while it is running.
The animation will take the changes into account on the next loop.
Change-Id: I2f560ee713666e67b7162d95ff28621fcf3b2545
Fixes: QTBUG-38932
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
44dd79eeda