Comment 9 for bug 1656664

Adding the class is just some dull work: Need to mind loading and saving, too.

Figuring out a way to get a list of
- other tribes' military buildings
- in working range of this scouting hut
- known to this tribe
- unattackable (vision range)
- in range of at least one own military building
- allies excluded

might take a while. I do not even know which terms the code uses for these things. The rest is straightforward.