VMs with `parent_` as a prefix oughta modify parameters as well as variables

[boot2big]

Suppose you've got a door_hood, and a part that modifies parent_door_hood. This works, and that's all good! However if you wanna modify something like wingArea, dragCoefficient, etc. then using parent_dragCoefficient doesn't work, meaning you've gotta modify the vehicle JSON with its own dC VM that reads a value on the part to make it happen anyways. That's no fun!

I'mma contribute as many of my don credits as needed for this.

[DonBruce64]

This will be done with the CV beta.