Fix FFTW unit test with clang
Fix sparse_product/sparse_extra unit tests
Fix compilation of SPlines module
Fix support for row (resp. column) of a column-major (resp. row-major) sparse matrix
Relaxed umeyama test. Problem was ill-posed if linear part was scaled with very small number. This should fix bug 744.

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extra : rebase_source : 531d4009f0b887bdf4a14e6985bc8dde02c3f85e