Panning in the Circuit Editor

[weerox]

The current way to pan (move around) the Circuit editor is holding the middle mouse button. This works very well for users with a mouse and it makes left and right click available for other actions, but for users on a laptop it makes panning quite difficult.

I can see two ways to get around this:

1. Add a tool specifically for panning.
2. In Inkscape, I can pan by moving two fingers across the mouse pad. I think that this might be my Macbook simulating middle mouse button + drag, but I'm not sure.

[NogginBops]

I like the idea of having a tool for panning (that also gets temporarily activated when pressing middle click).
Gtk should handle interpreting a double finger click on mousepads as a pan but this might be an option we haven't set or something similar.