Renovated the interpretCommand method, now spread across multiple objects including Location, Inventory and Landscape
Refactored making a lot more use of objects embedded on objects.
No longer using codes for locations.
Thing codes are only for the benefit of the command interpreter.
Lists of things, ways, and characters are no longer passed to location in a constructor.
Instead their constructors require the location as the first parameter.
Game data has been reorganised and visually simplified as a result.
Landscape class is gone.  Locations can be found as a set within the Location class.  Similar for things and characters.
doTurn and interpretCommand now hang off Character.