add AngularConstraint.* with some unit tests

more unit tests to follow
added tests for ConeRollerConstraint
delete AngularConstraints at end of tests
Add copy ctor for JointState

create AngularConstraint for joints that need them (but not used yet)
merge upstream/master into andrew/bispinor
merge andrew/ragdoll into andrew/bispinor

improved IK merged into AngularConstraint work

Conflicts:
	interface/src/renderer/JointState.cpp
	interface/src/renderer/JointState.h
add AngularConstraint::softClamp() for hands
re-enable gravity effect on arm IK
merge upstream/master into andrew/ragdoll
Merge pull request #3117 from AndrewMeadows/ragdoll

apply joint constraints during IK