Changes

Important to note, that ''extended_shadow_texture'' should not have shadows for wheels that are attached to axle models, while ''ui_shadow'' should have shadows for all wheels in their default position as the axle model is not moving in the UI.

There is now support for electric engines. Behavior of powertrain and few other aspects of vehicle is now defined by member ''type'' of the engine. Accepted values are ''electric'' and ''diesel'' (default, used if not specified or unknown).