Changes to support IterativeSolver, ContactGraph, and unchangeable mass
Changes to support IterativeSolver, ContactGraph, and unchangeable mass

Added Node and sleep fields for supporting the new ContactGraph class' graph traversal and sleeping optimization. Added flag to ignore collisions against the GObject's parent. Added copy method for collision Manifold. Removed directly setting acceleration and mass. Changed definition of static from a flag to any body with a mass of zero.

joltix/Cinnamon