Remove unused cable position functions
Remove string position from anchor constructor and data members (difficult to keep up to date)
Simplification of logic for muscleAnchor updates
Comments for muscleAnchor, cleanup of getManifoldDistance
Improvements to pruning procedure and manifold updates, comments
Deleting overlapping pair cache helps full structures
Changing return type of calculateAndApplyForce since no one looks at that force vector, many comments for MuscleNP
Two string test, silence couts from MuscleNP