Embree v2.16.5

• Bugfix in the robust triangle intersector that rarely caused NaNs.
• Fixed bug in hybrid traversal kernel when BVH leaf was entered with no
  active rays. This rarely caused crashes when used with instancing.
• Fixed bug introduced in Embree 2.16.2 which caused instancing not to
  work properly when a smaller than the native SIMD width was
  used in ray packet mode.
• Fixed bug in the curve geometry intersector that caused rendering
  artefacts for Bézier curves with p0=p1 and/or p2=p3.
• Fixed bug in the curve geometry intersector that caused hit results
  with NaNs to be reported.
• Fixed masking bug that caused rare cracks in curve geometry.
• Enabled support for SSE2 in precompiled binaries again.