separate muscle constraints from joint constraints
formatting and minor tweaks to constraint strengths
more perfstats for ragdoll simulation
add Shape::_id
namechange for Shape::_id
fix old copy-n-paste typo
fix old bug: rotation of CapsuleShape not updated

when setting endpoints directly
add PhysicsSimulation::_frame
remove unused Constraint::_type
add CollisionInfo::getShapePairKey()
set the shape ID in the ctor's NOT the dtor
minor cleanup
add ContactConstraint and use to impede muscles
update physics stats names
limit action of ContactConstraint to penetration
merge upstream/master into andrew/ragdoll
Merge pull request #3241 from AndrewMeadows/ragdoll

Ragdoll Part 7: introduction of ContactConstraint