Further clean-up of ode functions. * scripts/ode/private/AbsRel_Norm.m: Renamed to AbsRel_norm.m * scripts/ode/module.mk: Add AbsRel_norm.m to build system. * ode23.m, ode45.m: Remove extra comma from Copyright statement. Add ode45 to @seealso links in docstring. Add FIXME notes for questionable code. Use numel instead of length for clarity. Use space after function name and opening parenthesis. Wrap long lines to less than 80 characters. Change odemergeopts function call to match new prototype. Use single quotes to simplify strings that contain double quotes. Use 2-space indent in %!function blocks. * odeget.m: Remove extra comma from Copyright statement. Use double quote in preference to single quote. Delete whitespace at end of lines. * odeplot.m: Re-write docstring. Include @seealso links in docstring. Declare all persistent variables in a single declaration. Use in-place += operator for efficiency. Add FIXME notes for questionable code. * odeset.m: Remove extra comma from Copyright statement. Add additional calling form with 1 output and 0 inputs to docstring. Add FIXME notes for questionable code. Delete whitespace at end of lines. * odeset.m(print_options): Use single quotes to simplify strings with double quotes. Put default value of option first in list. * integrate_adaptive.m: Wrap long lines < 80 characters. Delete whitespace at end of lines. Correct indentation of declared values after '='. * kahan.m: Reise docstring. * ode_event_handler.m: Use retval in docstring to match functin prototype. Delete unnecessary comments. * odedefaults.m: Remove extra comma from Copyright statement. Match variable names in docstring to function prototype. Use space after function name and before opening parenthesis. Delete whitespace at end of lines. * odemergeopts.m: Remove extra comma from Copyright statement. Delete extra space in function prototype. Change function prototype to have "caller" as first argument to match rest of Octave. * runge_kutta_23.m: Clean up declaration of persistent variables. Correct misspellings in comments. * runge_kutta_45_dorpri.m: Put description of input arguments before output arguments in docstring. Clean up declaration of persistent variables. * runge_kutta_interpolate.m: Use double quotes in preference to single quotes. Eliminate line continuations for code that would fit on a single line. Remove obsolete code that calls non-existent functions. Capitalize Hermite in comments. Cleanup declaration of persistent variables. * starting_stepsize.m: Replace calls to AbsRel_Norm with AbsRel_norm.

## Copyright (C) 2016 Francesco Faccio <francesco.faccio@mail.polimi.it>
##
## This file is part of Octave.
##
## Octave is free software; you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 3 of the License, or (at
## your option) any later version.
##
## Octave is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING.  If not, see
## <http://www.gnu.org/licenses/>.

function options = odemergeopts (caller, useroptions, options, classes,
                                 attributes);

  for [value, key] = options;

    if (isfield (useroptions, key) && ! isempty (useroptions.(key)))

      if (! strcmp (classes.(key), "char"))
        validateattributes (useroptions.(key), classes.(key),
                            attributes.(key), caller, key);

      elseif (ischar (useroptions.(key)))
        validatestring (useroptions.(key), attributes.(key), caller, key);

      else
        error ("Octave:invalid-input-arg",
               [caller ": invalid value assigned to field '%s'"], key);
      endif

      options.(key) = useroptions.(key);

    endif

  endfor

endfunction