Blender Git Loki

Cycles: Replace T-SVD algorithm with new Jacobi Eigendecomposition solver

The code that was used for the T-SVD before came from the WLR reference implementation,
but had numerical problems on Windows and would often cause NaNs.

This commit replaces it with a new implementation using Eigendecomposition based on the Jacobi Eigenvalue Method.
That should:
- Give a slight performance boost (probably not noticable, since the T-SVD was no bottleneck to begin with)
- Improve numerical accuracy of the results (not very important either since the eigenvalues are only compared against a threshold)
- FINALLY solve the black spot issue on Windows
- Slightly reduce memory usage (singular values are now constructed on the diagonal of the input matrix) with the potential of more in the future (now only the lower-triangular part is required).
- Resolve potential licensing issues - the specific file containing the original code didn't come with any licensing information, and the main file contains an apparently custom license...