* new: unit stances: agressive, defensive, stand ground, and passive (aoe model)
* after combat, units return to their assigned position after a peacetime delay
* skirmish AI no longer builds mines outside its bases until a remote base is established
* QOL: campaign missions 6, 8 and 10 now show the objective target on the map only, with no offscreen indicator
* fix research progression breaking when the AI used research in skirmish
* fix enemy buildings playing the research complete voice-over