Embree

- Invalid multi segment motion blurred normal oriented curves are properly excluded from BVH build.
- Fixing issue with normal oriented curve construction when center curve curvature is very large.
Due to this change normal oriented curve shape changes slightly.
- Fixed crash caused by disabling a geometry and then detaching it from the scene.
- Bugfix in emulated ray packet intersection when EMBREE_RAY_PACKETS is turned off.
- Bugfix for linear quaternion interpolation fallback.
- Fixed issues with spaces in path to Embree build folder.
- Some fixes to compile Embree in SSE mode using WebAssembly.
- Bugfix for occlusion rays with grids and ray packets.
- We do no longer provide installers for Windows and macOS, please use the ZIP files instead.
- Upgrading to Intel® ISPC 1.17.0 for release build.
- Upgrading to Intel® oneTBB 2021.5.0 for release build.

- Avoiding spatial split positions that are slightly out of geometry bounds.
- Introduced rtcGetGeometryThreadSafe function, which is a thread safe version of rtcGetGeometry.
- Using more accurate rcp implementation.
- Bugfix to rare corner case of high quality BVH builder.

- Added support for Intel® ISPC ARM target.
- Releases upgrade to Intel® TBB 2021.3.0 and Intel® ISPC 1.16.1

- Added support for Apple M1 CPUs.
- RTC_SUBDIVISION_MODE_NO_BOUNDARY now works properly for non-manifold edges.
- CMake target 'uninstall' is not defined if it already exists.
- Embree no longer reads the .embree3 config files, thus all configuration has
to get passed through the config string to rtcNewDevice.
- Releases upgrade to Intel® TBB 2021.2.0 and Intel® ISPC 1.15.0
- Intel® TBB dll is automatically copied into build folder after build on windows.

- Fixed wrong uv and Ng for grid intersector in robust mode for AVX.
- Removed optimizations for Knights Landing.
- Upgrading release builds to use Intel® oneTBB 2021.1.1

- Changed default frequency level to SIMD128 for Skylake, Cannon Lake, Comet Lake and Tiger Lake CPUs.
This change typically improves performance for renderers that just use SSE by maintaining higher
CPU frequencies. In case your renderer is AVX optimized you can get higher ray tracing performance
by configuring the frequency level to simd256 through passing frequency_level=simd256 to rtcNewDevice.