Experimenting with physics simulation

1. Particle chain, no collision detection/response
2. Particle contact, with contact constraints (coolision detection and response)
3. Rigid body chain, same as #1 but with rigid solids
4. Stack vs Chain, a chain hits a stack
5. Stack vs Chain + Friction, a chain hits a stack, objects now experience friction.
6. Stack vs Chain + discs + Friction, same as #5 with now featuring discs.
7. Car driving, features a simple wheel model.

1. cache lambdas for each constraint