Merge remote-tracking branch 'upstream/master' into send_upstream
Backport changes from Houdini trunk

Only notable changes to two nodes:

- SOP_OpenVDB_Advect_Points.C
    - Add support for traillen attribute

- SOP_OpenVDB_Convert.C
    - Disable adding to seamPointGroup if we don't have pointFlags() to avoid
      out of bounds access leading to a crash. (bug #62017)
    - Use a half width of 3 voxels instead of 1 when converting fog VDBs to SDF.
    - Fix bug where converting fog volumes to SDF in Convert VDB ignored the
      isovalue. To ensure backwards compatibility, a new fogisovalue parameter
      is added that defaults to the old 0.5 value. (bug #61477)
Merge pull request #24 from sideeffects/send_upstream

Backport changes to VDB nodes from Houdini trunk
OpenVDB 3.0 beta
Sync with internal OpenVDB 3 branch.
Merge from upstream OpenVDB 3.0 changes

Merge remote-tracking branch 'upstream/master'

Conflicts:
	openvdb/CHANGES
	openvdb/INSTALL
	openvdb/Makefile
	openvdb/doc/changes.txt
	openvdb/io/Archive.cc
	openvdb/io/Compression.cc
	openvdb/io/Compression.h
	openvdb/io/File.cc
	openvdb/math/DDA.h
	openvdb/openvdb.cc
	openvdb/python/pyOpenVDBModule.cc
	openvdb/tools/Clip.h
	openvdb/tools/LevelSetTracker.h
	openvdb/tools/Morphology.h
	openvdb/tools/ParticlesToLevelSet.h
	openvdb/tools/PointIndexGrid.h
	openvdb/tools/PointPartitioner.h
	openvdb/tree/InternalNode.h
	openvdb/tree/LeafNode.h
	openvdb/tree/RootNode.h
	openvdb/tree/Tree.h
	openvdb/tree/Util.h
	openvdb/unittest/TestLeaf.cc
	openvdb/unittest/TestPointIndexGrid.cc
	openvdb/unittest/TestTools.cc
	openvdb/unittest/TestTree.cc
	openvdb/unittest/TestVolumeRayIntersector.cc
	openvdb/version.h
	openvdb_houdini/Makefile
	openvdb_houdini/houdini/GEO_PrimVDB.cc
	openvdb_houdini/houdini/GEO_VDBTranslator.cc
	openvdb_houdini/houdini/GU_PrimVDB.cc
	openvdb_houdini/houdini/GU_PrimVDB.h
	openvdb_houdini/houdini/SOP_OpenVDB_Combine.cc
	openvdb_houdini/houdini/SOP_OpenVDB_Convert.cc
	openvdb_houdini/houdini/SOP_OpenVDB_Fracture.cc
	openvdb_houdini/houdini/SOP_OpenVDB_From_Particles.cc
	openvdb_houdini/houdini/SOP_OpenVDB_Write.cc
	openvdb_houdini/houdini/geometry.h
Visual C++ fixes
updated NodeManager
Merge remote-tracking branch 'upstream/master'