Introduce realistic size vehicle

Once we've managed to show a marker at the current vehicle location it would be good to show a realistic size object.

A 100m long cylinder would be suitable for this.

Better still some kind of 3d rendered object freely downloaded off the web. I don't know what model formats (if any) are supported by NWW, but I'm happy with any 'ship-like' representation you can find. We'll create some custom models once we've learned more about it.