make all permutation matrices column permutations (bug #42418) Making all permutation matrices column permutations allows permutation matrices to be iterated over in column-major order just like any other matrix. * PermMatrix.h, PermMatrix.cc (PermMatrix::_colp): Delete member variable and all uses. (PermMatrix::transpose): Create new matrix with internal representation flipped. (PermMatrix::pos_power): New function. (PermMatrix::eye): Call the one-argument constructor which already defaults to the identity matrix. (PermMatrix::is_col_perm): Unconditionally return true. (PermMatrix::is_row_perm): Unconditionally return false. (PermMatrix::data, PermMatrix::fortran_vec, PermMatrix::pvec): Delete. (PermMatrix::col_perm_vec): New function. * lu.cc: New test. * base-lu.cc (base_lu<lu_type>::base_lu): Call transpose in ipvt initialization. * find.cc, kron.cc, pr-output.cc, ov-perm.cc, PermMatrix.cc, PermMatrix.h, Sparse.cc, dMatrix.cc, fMatrix.cc, CmplxQRP.cc, base-lu.cc, dbleQRP.cc, fCmplxQRP.cc, floatQRP.cc, Sparse-perm-op-defs.h, mx-op-defs.h: Adapt to PermMatrix changes.

gnulib-hg = gnulib-hg