QScroller fails sporadically when only one axis is scrollable

When using QScroller for pan-scrolling, the scrolling will frequently freeze if only one axis is scrollable.

The reason is that handleDrag only updates the lastPosition of scrollable axes, while using position-lastPosition to determine axislock. This means that if the total movement along a non-scrollable axis is larger than the time-delta-movement along a scrollable axis the event will be discarded.