Add gas bomber skill-shot vessel

Fleet.gd

@@ -86,6 +86,31 @@ func vessel_types() -> PackedStringArray:
 	return result
 
 
+func has_vessel_type(vessel_type: String) -> bool:
+	for ship in ships:
+		if is_instance_valid(ship) and String(ship.vessel_type) == vessel_type:
+			return true
+	return false
+
+
+func first_vessel_of_type(vessel_type: String) -> Node2D:
+	for ship in ships:
+		if is_instance_valid(ship) and String(ship.vessel_type) == vessel_type:
+			return ship
+	return null
+
+
+func has_capability(capability: String) -> bool:
+	return first_ship_with_capability(capability) != null
+
+
+func first_ship_with_capability(capability: String) -> Node2D:
+	for ship in ships:
+		if is_instance_valid(ship) and ship.has_capability(capability):
+			return ship
+	return null
+
+
 func add_ship(vessel_type: String = GameState.VESSEL_INTERCEPTOR) -> bool:
 	# Adds one vessel in the next free formation slot (bought from a ship
 	# crafter). Returns false when the wedge is already full.