The swipe handler is simple, and also doesn't currently work on every
platform. But the pinch handler is the one that needs explanation,
because the difference between incremental and absolute values of the
rotation and scale properties is tricky.
Change-Id: Ie3c7f4941d4a17734c9a920a8dd978f86fb03c4b
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>