Added squadron configuration gui

- added add/remove buttons to Air Wing Menu, implemented remove

game/observer.py

@@ -0,0 +1,21 @@
+class Event(object):
+    pass
+
+
+class Observable(object):
+    def __init__(self) -> None:
+        self.callbacks = []
+
+    def subscribe(self, callback) -> None:
+        self.callbacks.append(callback)
+
+    def unsubscribe(self, callback) -> None:
+        self.callbacks.remove(callback)
+
+    def fire(self, **attrs) -> None:
+        e = Event()
+        e.source = self
+        for k, v in attrs.items():
+            setattr(e, k, v)
+        for fn in self.callbacks:
+            fn(e)

game/squadrons/airwing.py

@@ -9,19 +9,39 @@ from gen.flights.ai_flight_planner_db import aircraft_for_task
 from gen.flights.closestairfields import ObjectiveDistanceCache
 from ..theater import ControlPoint, MissionTarget
 
+from ..observer import Observable
+
 if TYPE_CHECKING:
     from ..ato.flighttype import FlightType
     from .squadron import Squadron
 
 
-class AirWing:
+class AirWing(Observable):
     def __init__(self, player: bool) -> None:
+        super().__init__()
         self.player = player
         self.squadrons: dict[AircraftType, list[Squadron]] = defaultdict(list)
 
     def add_squadron(self, squadron: Squadron) -> None:
+        new_aircraft_type = squadron.aircraft not in self.squadrons
+
         self.squadrons[squadron.aircraft].append(squadron)
 
+        if new_aircraft_type:
+            self.fire(type="add_aircraft_type", obj=squadron.aircraft)
+        self.fire(type="add_squadron", obj=squadron)
+
+    def remove_squadron(self, toRemove: Squadron) -> None:
+        if toRemove.aircraft in self.squadrons:
+            self.squadrons[toRemove.aircraft].remove(toRemove)
+            self.fire(type="remove_squadron", obj=toRemove)
+            if len(self.squadrons[toRemove.aircraft]) == 0:
+                self.remove_aircraft_type(toRemove.aircraft)
+
+    def remove_aircraft_type(self, toRemove: AircraftType) -> None:
+        self.squadrons.pop(toRemove)
+        self.fire(type="remove_aircraft_type", obj=toRemove)
+
     def squadrons_for(self, aircraft: AircraftType) -> Sequence[Squadron]:
         return self.squadrons[aircraft]