Xpand Rally Car Importer file

- Custom Cars Wizard - a tool for importing custom cars and allowing customization of cars parameters
- Game 3D mesh exporting plugin that allows the use of custom objects (including cars) created in 3D Studio Max in the game
- 3D Studio Max script that processes the car's mesh and prepares it for the use in the game
- Sample car mesh - 3D Studio Max source file and XR custom car ready files