chol: return permutation vector as row vector instead of column vector. * libinterp/dldfcn/chol.cc: add tests for the vector option. Also error if there's a "vector" option but input was not sparse. Existing test for case sensitivity was also useless, since change is on the 3rd argument. * liboctave/numeric/sparse-chol.cc, liboctave/numeric/sparse-chol.h: use RowVector instead of ColumnVector for permutation vector, for Matlab compatibility.

gnulib = http://hg.octave.org/gnulib