v0.4.0 test 2: rival avatars

This new test version has a  bug fix:

- L3 engines should now work properly. (Changed some values in the clutch that made the torque transfer from engine to wheels go haywire.)

It also introduces rival avatars. Thank you ChatGPT, because I couldn't draw those myself, but these are from left to right respectively: Mr X, driving the white Porsche 959, Jimbo, currently driving the yellow Porsche 911 (which is going to be a new car someday), Kris, driving a red Corvette and ... I'm not going to tell the last one. You'll figure that out if you play the game.

They are supposed to talk to you before and after the race, but only Mr X has most of his lines. I even haven't fully tested everything, so it might even crash. Let me know if that happens. (I really need some more sleep...)