Touchpad movements need work

[eugenialoli]

I used two fingers on the touchpad in the working area, and then it all became so small, that even "zoom to fit" wouldn't show the working area! No matter if I did pinch in or out, it would become miniscule, and it was very difficult to get it visible again.

I've noticed a similar problem with QCAD and touchpads, however on the same machine, LibreCAD has this issue resolved, so I know it can be a better experience.

[rodlie]

I decided to implement proper multi touch and gesture support on macOS first (as it has the best implementation), support for Win/Lin will be added in v1.1.

[eugenialoli]

Thank you!