added Nitro and Weight Class to bomber/cargo printouts #27
print page bomber turrets added. #27
added sprite classes for bomber turrets #27
finished bomber turrets and layout for bomb bays #27
added file version attribute for updating files to new xml structures.
added BombLoadout class #38
page bombs/cargo becomes cargo only page. see #38 and #36
finished bomber print page 2. see #27
cleanup