The watch of scenery files asked three times per file, whether it is there,
its time and its size, every two seconds for every source of every scenery.
One look gives all three.
A failed write leaves the old file in place. Settings that could not be read
are not saved over. UI exceptions reach the log. Started from a shortcut set
up elsewhere, the starter moves to its own folder when only that one holds a
game.
VehicleDatabase becomes VehicleCatalog, Physics becomes VehiclePhysics, and the
textures.txt and .fiz parsers move to Infrastructure. GameLibrary replaces the
GameData singleton.
