Translate patch property listeners to C++ (bug #42159) * graphics.in.h (patch::properties::bad_data_msg): new private attribute to store the updaters warnings * graphics.in.h (patch::properties::has_bad_data(std::string &msg)): new public method * graphics.in.h (patch::properties::x/ydata): change default values to be consistent with default faces/vertices * graphics.in.h (patch::properties::faces/vertives/facevertexcdata): add updaters * graphics.in.h (patch::properties::update_fvc/update_data): declare new methods * graphics.in.h (patch::properties::update_x/y/z/cdata): use new update_fvc method * graphics.in.h (patch::properties::update_faces/vertices/facevertexcdata): use new update_data method * gl-render.cc (opengl_renderer::draw_patch): do not render if the patch has incorrect data * graphics.cc (default_patch_x/ydata (void)): new functions * graphics.cc (patch::properties::update_data/fvc): new methods, translated from former setvertexdata and setdata (__patch__.m) except "facecolor" is not updated (matlab compatibility). When incoherent data are found, a warning message is stored in bad_data_msg. * graphics.cc: new static variable updating_patch_data to prevent recurrent calls to update_data and update_fvc * __patch__.m: remove listeners * patch.m: small correction in a demo to take into account the fact "facecolor" is no more updated

To cite GNU Octave in publications use:

  John W. Eaton, David Bateman, Søren Hauberg, Rik Wehbring (2014).
  GNU Octave version 3.8.1 manual: a high-level interactive language for
  numerical computations.
  CreateSpace Independent Publishing Platform.  ISBN 1441413006,
  URL http://www.gnu.org/software/octave/doc/interpreter/

A BibTeX entry for LaTeX users is:

  @book{,
    author    = {John W. Eaton, David Bateman, S\oren Hauberg, and Rik Wehbring},
    title     = {{GNU Octave} version 3.8.1 manual: a high-level interactive language for numerical computations},
    publisher = {CreateSpace Independent Publishing Platform},
    year      = {2014},
    note      = {{ISBN} 1441413006},
    url       = {http://www.gnu.org/software/octave/doc/interpreter},
  }

We have invested a lot of time and effort in creating GNU Octave, please cite it
when using it.  See also `citation pkgname' for citing Octave packages.