OSPRay v1.2.0

• Added support for volumes with voxelType short (16-bit signed
  integers). Applications need to recompile, because OSPDataType has
  been re-enumerated
• Removed SciVis renderer parameter aoWeight, the intensity (and now
  color as well) of AO is controlled via "ambient" lights. If
  aoSamples is zero (the default) then ambient lights cause ambient
  illumination (without occlusion)
• New SciVis renderer parameter aoTransparencyEnabled, controlling
  whether object transparency is respected when computing ambient
  occlusion (disabled by default, as it is considerable slower)
• Implement normal mapping for SciVis renderer
• Support of emissive (and illuminating) geometries in the path tracer
  via new material "Luminous"
• Lights can optionally made invisible by using the new parameter
  isVisible (only relevant for path tracer)
• OSPRay Devices are now extendable through modules and the SDK.
• Devices can be created and set current, creating an alternative
  method for initializing the API
• New API functions for committing parameters on Devices
• Removed support for the first generation Intel® Xeon Phi™ coprocessor
  (codename Knights Corner)
• Other minor improvements, updates, and bugfixes:
• Updated Embree required version to v2.13.0 for added features
  and performance
• New API function ospDeviceSetErrorMsgFunc() to specify a
  callback for handling message outputs from OSPRay
• Add ability to remove user set parameter values with new
  ospRemoveParam() API function
• The MPI device is now provided via a module, removing the need
  for having separately compiled versions of OSPRay with and
  without MPI
• OSPRay build dependencies now only get installed if
  OSPRAY_INSTALL_DEPENDENCIES CMake variable is enabled