OSX: wheel events are sent with the wrong global position by qnsview.mm

qnsview.mm sends wheel events like so:

QWindowSystemInterface::handleWheelEvent(m_window, qt_timestamp, qt_windowPoint, qt_windowPoint, pixelDelta, angleDelta,
                                                 [self convertKeyModifiers:[theEvent modifierFlags]]);

Note qt_windowPoint being passed twice – the second time is as the global position, which is obviously wrong. This affect things like scrolling in QGraphicsView.

The fix is simple. I've attached a patch.