Slightly improve modifier key detection.
Beware the duck.

Duck can now sabotage factories, causing production to slow down.
hot air balloons, because why not
give the hot air balloon an icon
Add team colour textures for some units.
Merge branch 'hot-air-balloons' of http://git.scgtrp.net/blarg2.git/

Conflicts:
	Assets/Resources/Barracks.prefab
	Assets/Scripts/Units/Vehicle.cs
Update prefabs & materials for team colours.