OSPRay v2.0.1

• Fix bug where Embree user-defined geometries were not indexed correctly
  in the scene, which now requires Embree v3.8.0+
• Fix crash when the path tracer encounters geometric models that do not
  have a material
• Fix crash when some path tracer materials generated NULL bsdfs
• Fix bug where ospGetBounds returned incorrect values
• Fix missing symbol in denoiser module
• Fix missing symbol exports on Windows for all OSPRay built modules
• Add the option to specify a single color for geometric models
• The scivis renderer now respects the opacity component of color on
  geometric models
• Fix various inconsistent handling of frame buffer alpha between renderers
• ospGetCurrentDevice now increments the ref count of the returned
  OSPDevice handle, so applications will need to release the handle when
  finished by using ospDeviceRelease accordingly
• Added denoiser to ospExamples app
• Added module_mpi to superbuild (disabled by default)
• The superbuild now will emit a CMake error when using any 32-bit CMake
  generator, as 32-bit builds are not supported