Store the owning coalition in ControlPoint.

This is needed fairly often, and we have a lot of Game being passed
around to ControlPoint methods specifically to support this. Just store
the owning Coalition directly in the ControlPoint to clean up. I haven't
cleaned up *every* API here, but did that aircraft allocations as an
example.

game/game.py

@@ -123,6 +123,9 @@ class Game:
         self.blue.set_opponent(self.red)
         self.red.set_opponent(self.blue)
 
+        for control_point in self.theater.controlpoints:
+            control_point.finish_init(self)
+
         self.blue.configure_default_air_wing(air_wing_config)
         self.red.configure_default_air_wing(air_wing_config)