Merge pull request #16 from sideeffects/send_upstream

Fix math::Abs() truncation for non-Windows platforms
Various fixes
Merge branch 'master' of ssh://github.com/dreamworksanimation/openvdb_dev
Merge pull request #17 from sideeffects/send_upstream

Add missing openvdb.h #include in RayIntersector.h
Version 2.3.0
Merge branch 'master' of ssh://github.com/dreamworksanimation/openvdb_dev
Fix LeafNodeBool::Buffer::getValue() to NOT return the address of a temporary when compiled with Visual C++.