add AACube::operator<() so they can be sorted
init Shape::_mass in all ctors
add findContentInCube() and typedef CubeList
add PhysicsEntity::stepForward()
use PhysicsEntity::stepForward() in simulation loop
add VoxelShapeManager class
give MyAvatar a VoxelShapeManager member
merge upstream/master into andrew/ragdoll
fix for nan in sphereVsAACubeHelper()
merge upstream/master into andrew/ragdoll
use QHash, not QVector, for Octree content query
remove unecessary AACube::operator<()
clarify how the size of the cube is computed
Merge pull request #3343 from AndrewMeadows/ragdoll

Ragdoll Part 12: first pass avatar skeleton collides with voxels