Avoid problematic ternary operator (http://forum.kde.org/viewtopic.php?f=74&t=109486)
Fix array unit test: isApprox(log(0),log(0)) is false, and summing up signed float value might result in very small values and thus large numerical errors
Fix another issue related to summing up many signed values.
Cleaning pass on SparseQR
Extend sparseqr unit test to check linearly dependent columns
Remove superfluous cast.
Fix bug 496: generalize internal rank1_update implementation to accept uplo(A) += v * w and make A.triangularView() += v * w uses it.
Update unit tests and blas interface respectively.