Bug 871: fix compilation on ARM/Neon regarding __has_builtin usage
Fix regression is sparse-sparse product
Reafctoring in D&C SVD unsupported module: clean and merge the SVDBase class to Eigen/SVD, rm copy/pasted JacobiSVD.h file

--HG--
rename : unsupported/Eigen/src/SVD/SVDBase.h => Eigen/src/SVD/SVDBase.h
rename : unsupported/Eigen/SVD => unsupported/Eigen/BDCSVD
rename : unsupported/Eigen/src/SVD/BDCSVD.h => unsupported/Eigen/src/BDCSVD/BDCSVD.h
rename : unsupported/Eigen/src/SVD/CMakeLists.txt => unsupported/Eigen/src/BDCSVD/CMakeLists.txt
rename : unsupported/Eigen/src/SVD/TODOBdcsvd.txt => unsupported/Eigen/src/BDCSVD/TODOBdcsvd.txt
rename : unsupported/Eigen/src/SVD/doneInBDCSVD.txt => unsupported/Eigen/src/BDCSVD/doneInBDCSVD.txt