Added Furniture3 and Furniture4 layers to BuildingEd.
Fixed stacking order when copying objects in BuildingEd.
Removed the 'Lot directory:' entry from the Preferences.
Removed some unused code.
Added "Open in TileZed" to object-tool context menu.

This will open a Lot map.
Fixed ObjectSelectionTool not having a context menu.
Improvements to "Convert To Lot".

Fixed the map-file browse-button not doing anything.
Fixed not being able to add a lot-object the the top-most ObjectGroup.
Allow replacing an existing file.
Added checkbox for choosing Isometric or LevelIsometric orientation.
Added checkbox for opening the new lot in TileZed.

RoomDef objects are now added to the new lot map.
Fixed display issue when an already-loaded map's orientation changed.