Embree v2.16.2

• Fixed bug that caused NULL intersection context in intersection filter when instancing was used.
• Fixed an issue where uv's where outside the triangle (or quad) for very small triangles (or quads). In robust mode we improved the uv calculation to avoid that issue, in fast mode we accept that inconsistency for better performance.
• Changed UV encoding for non-quad subdivision patches to allow a subpatch UV range of [-0.5,1.5[. Using this new encoding one can use finite differences to calculate derivatives if required. Please adjust your code in case you rely on the old encoding.