Damage System 1/2 (0.1.5.1)

Damage system implementation for cars. 

• Both engines and cars now have visual damage when lower durability
• Engines will now be unusable if a part is at 0% durability
• Engine parts perfromance is now also dependent on durability
• Engines can take damage from improper modification of the engine, such as having too much horsepower for the internals, overheating, or having too much boost/compression.

Part 2 of this update will include damage for car parts when colliding with objects and some way to repair damaged parts.