Minimum gnuplot version for Octave 4.2?

[Rik]

9/14/16

Is there any objection to requiring a minimum gnuplot version of 4.4 for
the next release?  The release date was March 2010, or 6.5 years ago.  The
4.2 series had a release date of April 2007, but I don't think anyone has
tried to use Octave with gnuplot 4.2.X and I'm not really sure it would
work anymore.  In our own README.gnuplot we say, "Octave works best with
gnuplot 4.4 or higher, which is available from http://www.gnuplot.info.";

I happened to notice in the documentation for image() that we still have
"*Warning:* X and Y are ignored when using gnuplot 4.0 or earlier." which
is horrendously out of date.

--Rik