OSPRay v2.3.0

• Re-add SciVis renderer features (the previous version is still
  available as ao renderer)
  • Lights are regarded, and thus the OBJ material terms ks and
    ns have effect again
  • Hard shadows are enabled via the shadows parameter
  • The control of ambient occlusion changed:
    • The aoIntensity parameter is replaced by the combined
      intensity of ambient lights in the World
    • The effect range is controlled via aoDistance
• Added support for data arrays with a stride between voxels in
  volumes
• Application thread waiting for finished image via ospWait
  participates in rendering, increasing CPU utilization; via
  rkcommon v1.5.0
• Added ospray_cpp compatibility headers for C++ wrappers to
  understand rkcommon and glm short vector types
  • For rkcommon, include ospray/ospray_cpp/ext/rkcommon.h
  • For glm, include ospray/ospray_cpp/ext/glm.h
  • Note in debug builds some compilers will not optimize out type trait
    definitions. This will require users to manually instantiate the glm
    definitions in one translation unit within the application using
    #define OSPRAY_GLM_DEFINITIONS before including ext/glm.h: see
    ospTutorialGLM as an example
• Changed parameters to volume texture: it now directly accepts the
  volume and the transferFunction
• Fixed many memory leaks
• Handle NaN during volume sampling, which led to bounding boxes
  being visible for some volumes and settings
• Depth is now "accumulated" as well, using the minimum
• Fix shading for multiple modes of the debug renderer
• New minimum ISPC version is 1.14.1