Add middle mouse button and shortcuts

[hromamk]

Middle mouse button (as well as other additional mouse buttons) are ignored in they key binding. I have to remap them to other keyboard buttons for them to be usable.. it's silly.

You already have shift+ and other combinations possible in the "accessibility" menu, why not unify it and just make shift+*/alt+*/ctrl+* bindable in the key binding menu, the game has enough actions and menus for this to be possible. For example I'd bind alt+1...5 for info/skills/health/protection/temperature.

Also why isn't construction/deconstruction a bindable button?