[Pkg-emacsen-addons] Bug#944249: Bug#944249: gnuplot-mode does not work with emacs26

[Dima Kogan]

OK. I went through all the patches, and pushed a tree to git. Nicholas:
I took most of your stuff, except I don't want to rename the package
again.

I'll move the repo to the emacs team this week, and we can do an upload.
Nicholas: do you want to be an Uploader? And are you an emacs team
member? You can then get rights to write to the repo. And if you want
to, you can prepare the final package that I'll then upload for you.