added rsplit. fixed rsearch for a case when both string and pattern are empty.
incorporated comments and corrections
Merge pull request #3477 from tanmaykm/rsplit

added rsplit. fix rsearch for case when both string and pattern are empty
Make workspace larger in xbdsdc to avoid segfault when uplo='L'.
Some linalg changes. A new general matrix factorization method. A Julia implementation of gelsy. Some changes to the treatment of symmetric and hermitian matrices and some bug fixes. And some tests.
Merge pull request #3315 from JuliaLang/anj/factorize

RFC: factorize() and \