Blender Git Loki

Merge branch 'openvdb' into cvdb_ray_isect

Conflicts:
intern/cycles/kernel/kernel_textures.h
intern/cycles/kernel/kernel_volume.h
intern/cycles/render/attribute.cpp
intern/cycles/render/scene.h
intern/cycles/render/session.cpp
intern/cycles/render/shader.cpp
intern/cycles/util/util_task.cpp