Jet engine exhaust visual effects

Finally implemented supersonic jet engine exhaust operation modes depending on ambient pressure.
Now there are visual effects such as underexpanded and overexpanded depending on the altitude.

Also implemented a few supersonic jet exhaust visual attributes such as shock diamonds and carbon traces.

Shock diamonds are caused by air pressure difference at the exit from the nozzle and ambient pressure.

Carbon traces are dark (relatively to the rest of the flame surface) stripes right at the exit of the jet engine. They are the remaining's of the unburnt fuel injected between main stream and engine wall to protect it from melting.

The visuals are not in the posted game yet. But will be included in the upcoming release.