Calculate non-linear response function.

- Compute the response function between each pair of images, taking into account that it is not linear in the higher values. Use a spline to fit the samples, with Alglib.
- Link against Alglib.
- Use OpenMP and strip debug symbols only in the Release build.
- New CFAPattern class that represents a CFA pattern (Bayer or XTrans)
Add Alglib to CMakeLists.txt
Copy OpcodeList tags from DNG source images.