New Release package - gnuplot version 5.4

[Ethan A M. <me...@uw...>]

Gnuplot version 5.4 - first release

I have placed a source tarball for 5.4 on SourceForge

   https://sf.net/projects/gnuplot/files/gnuplot/5.4.0/gnuplot-5.4.0.tar.gz

Release Notes with new feature list

   http://gnuplot.info/ReleaseNotes_5_4.html

Version 5.4.0 is the start of a new "major release" series.
It supersedes version 5.2, first released in September 2017.

I realize that there may be unresolved issues with building Windows binaries
for Windows 10, but I decided that it is not reasonable to hold up release any
longer for issues that appear to be more related to system configuration than to
the gnuplot source.  If necessary we can put out a Windows-specific patchlevel 1.
As always, I am totally reliant on and extremely grateful to the volunteers
who put together Windows binaries from a source release package.

        cheers, and happy plotting

                Ethan