Experimental Moonhawk I6 Clubsport 0.21

This is the 0.21 Hotfix, 0.2 update was cancelled, had a weird issue where the packed DDS textures wouldn't work, yet unpacked they would - really really weird. So this 0.21 update is back to PNG textures for now, will return to DDS once I've nailed down the issue - in the mean time, here's the original 0.2 notes...

So I consider this 0.2 to be the first kind of semi-official-half-way-there kind of update, the changelog:

• Fully modeled and (non-normals) textured I6 with major tidy up revisions to block, inlet and headers, custom branded "clubsport" rocker cover and "Super-Intake" induction.
• Revised I6 torque curve based on data from MANY real world I6 engines, now the I6 is happy to run a "reasonable" amount of Nitrous Oxide.
• Purpose-developed CS Close-ratio gearbox to keep the engine on-song better than any of the stock configurations.
• Revised stock suspension setup. Still user tune-able.

WIP for next release:

• Supercharged configuration, fully modeled super-charger install with appropriate power delivery.

Maybe in a future release:

• Custom bonnet-scoop for super-charged variant.