Multiple Aircraft support, bugfix

Aircraft:
-modified update()
+bugfix for repeatedly forcing Airport to be inactive after takeoff

Airport:
-loadImage() is now a private static function

GameWindow:
-Airport related variables are now arrays
+airportControlBox -> airportControlBoxes
+airportControl -> airportControls
+airport -> airports
!these are still initialized using hard-coded values
-game logic merged with Master to support airport changes
-Airport helper functions now return any found airport, rather than
Booleans
+isArrivalsClicked() -> getArrivalsClicked()
+isDeparturesClicked() -> getDeparturesClicked()
-setAreas() modified
+now allocates fixed with to Plane info and Altimeter
+shares the rest between any AirportControls and the orders