 Cloak; AircraftTypes and BuildingTypes can now be cloakable


Cloakable AircraftTypes and BuildingTypes


Until now, AircraftTypes and BuildingTypes have ignored the
existence of Cloakable=yes. Now, if this tag is included on the entry of
a BuildingType or AircraftType, it will cloak.

 \ AircraftTypes will decloak when told to attack, not once
  they are within firing range.

 0.2
