#3 Implicit Joint destruction for GearJoint?

[Melvyn May]

AFAIK, the GearJoint depends other joints but that's isn't part of the base Joint (which relies on two bodies) thus when removing a joint, it would be nice if implicit joint destruction took place as well.

This would require having a joint-list on each joint. This would (for now) only be used via on revolute & prismatic joints when they're referenced by the gear-joint.

[Erin Catto]

This is a weakness of gear joints. It should be fixable with some special case logic.