* Migrate lots of pulling logic out of the components and clean it up
* It's buggy, but move more code out of the pullable component
* Pulling system now throws less errors than it did before the refactor
* Finally finish the big parts of refactoring pullability
* Pulling: Handle disconnect properly if the pull joint has been removed by physics shutdown
* Port 2b68449328 to this branch
* Changes as per PR reviews
* Port e801ffac45 (SharedJointSystem) and fix issues encountered during testing
SharedJointSystem.
Also, MinLength and Stiffness appear to have suddenly gained enough meaning that pulling is broken unless they're set.
20kdc
Leon Friedrich
DrSmugleaf