Gnuplot 5.4.7 release

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

The gnuplot version 5.4.7 release is now available for download from
SourceForge, including Windows binaries.

    https://sourceforge.net/projects/gnuplot/files/gnuplot/5.4.7

There is no change from the testing version.

Release notes:

    https://gnuplot.sourceforge.net/ReleaseNotes_5_4_7.html

	Ethan