Fix jumpy zooming when panning and zooming

I noticed an issue where if you zoom (2 finger pinch), then let go of one finger, pan around, then zoom again, the second zoom would jump in the very beginning. This seems to be caused by the fact that pointer1 and pointer2 are only updated in touchDragged if pinching is true. Moving the update calls outside of the pinching if statement solves the issue for me. I haven't noticed any regressions from this change.