RT#87984: plot3d does not accept an arrayref as its first data argument

[mohawk2]

@djerius writes on https://rt.cpan.org/Ticket/Display.html?id=87984:

The documentation indicates that arrayrefs[*] are acceptable as
data arguments. It looks like that's not quite the case for the
first argument to plot3d

pdl> plot3d( [0],[0],[0] )
term is wxt
Runtime error: Can't call method "ndims" on unblessed reference at /proj/axaf/ots/pkgs/perl-5.16/x86_64-linux_debian-6.0/lib/site_perl/5.16.3/PDL/Graphics/Gnuplot.pm line 3209, <DATA> line 90.

pdl> plot3d( pdl(0),[0],[0] )
Gnuplot warning: empty x range [0:0], adjusting to [-1:1]

Gnuplot warning: empty y range [0:0], adjusting to [-1:1]

Gnuplot warning: empty z range [0:0], adjusting to [-1:1]

[*] The documentation actually uses the term "listref", but technically there's no such thing in Perl. There are lists, by they are ephemeral and you can't take a reference to them. "listref" should be replaced by "arrayref".

@devel-chm adds:

This problem is still present as of PDL::Graphics::Gnuplot 2.000 with PDL-2.007_01 on cygwin+win7

This issue is still present as of PDL::Graphics::Gnuplot 2.000