[Feature Request] Support tablet & multitouch input options

[skarik]

Working on the Microsoft Surface, all interaction is treated as left-mouse-click, and this program requires a mouse plugged in. When working on a windows laptop, I have a similar issue in functionality and require a mouse. In both cases, detection of scroll on mousepads is spotty, mostly limited to zooming except for rare cases.

I would love to see proper tablet input support, to really dig into some High Performance Planning, and get to some sleek zoom and pan.

(I have experience with implementing it in C/C++ and have the required hardware for testing it on Windows. While I do not know Go, I may add this myself if I continue to use this excellent program.)