Windows Touchscreen Pinch Zoom not working

[JamesFrederik]

On Windows x64, it is possible to zoom the canvas using pinch action on a trackpad.
Which is very nice.

But, pinch zoom does not work on a touchscreen.

To Reproduce
Steps to reproduce the behavior:

1. Perform Pinch zoom action on a touchscreen.

Expected behavior
Zoom around centroid of pinch

[rbreu]

To be honest, I haven't looked into touch screen support at all yet. I will, but there are a couple of other things I want to get to first.