Fix Porsche 944, now the normal version, but still not the final one.

Improvements:
- PBR, improved light, improved materials;
- Improved suspension, made the characteristics of the engines similar to the real ones, added a model of the motor;
- New sound;
- Added 4 sets of wheels, a set of bumpers, racing seats, two types of steering wheel;
- Removed the dummy parts;
- Configs have been redesigned;
- Minor improvements on the zhibim.