maint: Use new C++ archetype in more files. Place input validation first in files. Move declaration of retval down in function to be closer to point of usage. Eliminate else clause after if () error. Use "return ovl()" where it makes sense. * find.cc, gammainc.cc, gcd.cc, getgrent.cc, getpwent.cc, givens.cc, graphics.cc, help.cc, hess.cc, hex2num.cc, input.cc, kron.cc, load-path.cc, load-save.cc, lookup.cc, mappers.cc, matrix_type.cc, mgorth.cc, nproc.cc, ordschur.cc, pager.cc, pinv.cc, pr-output.cc, profiler.cc, psi.cc, quad.cc, rcond.cc, regexp.cc, schur.cc, sighandlers.cc, sparse.cc, str2double.cc, strfind.cc, strfns.cc, sub2ind.cc, svd.cc, sylvester.cc, symtab.cc, syscalls.cc, sysdep.cc, time.cc, toplev.cc, tril.cc, tsearch.cc, typecast.cc, urlwrite.cc, utils.cc, variables.cc, __delaunayn__.cc, __eigs__.cc, __glpk__.cc, __magick_read__.cc, __osmesa_print__.cc, __voronoi__.cc, amd.cc, audiodevinfo.cc, audioread.cc, chol.cc, colamd.cc, dmperm.cc, fftw.cc, qr.cc, symbfact.cc, symrcm.cc, ov-bool-mat.cc, ov-cell.cc, ov-class.cc, ov-classdef.cc, ov-fcn-handle.cc, ov-fcn-inline.cc, ov-flt-re-mat.cc, ov-java.cc, ov-null-mat.cc, ov-oncleanup.cc, ov-re-mat.cc, ov-struct.cc, ov-typeinfo.cc, ov-usr-fcn.cc, ov.cc, octave.cc: Use new C++ archetype in more files.

--- a/libinterp/corefcn/svd.cc	Fri Dec 18 16:22:53 2015 -0500
+++ b/libinterp/corefcn/svd.cc	Fri Dec 18 15:37:22 2015 -0800
@@ -124,8 +124,6 @@
 @seealso{svd_driver, svds, eig, lu, chol, hess, qr, qz}\n\
 @end deftypefn")
 {
-  octave_value_list retval;
-
   int nargin = args.length ();
 
   if (nargin < 1 || nargin > 2 || nargout == 2 || nargout > 3)
@@ -133,18 +131,20 @@
 
   octave_value arg = args(0);
 
-  octave_idx_type nr = arg.rows ();
-  octave_idx_type nc = arg.columns ();
-
   if (arg.ndims () != 2)
     error ("svd: A must be a 2-D matrix");
 
+  octave_value_list retval;
+
   bool isfloat = arg.is_single_type ();
 
   SVD::type type = ((nargout == 0 || nargout == 1)
                     ? SVD::sigma_only
                     : (nargin == 2) ? SVD::economy : SVD::std);
 
+  octave_idx_type nr = arg.rows ();
+  octave_idx_type nc = arg.columns ();
+
   SVD::driver driver = static_cast<SVD::driver> (Vsvd_driver);
 
   if (nr == 0 || nc == 0)