Add gnuplot documentation as source

Documentation is part of the gnuplot source code, available at: - https://sourceforge.net/p/gnuplot/gnuplot-main/ci/master/tree/docs/ This can be redistributed, according the the Copyright (emphasis mine): > * Copyright 1986 - 1993, 1998, 2004 Thomas Williams, Colin Kelley > * > * Permission to use, copy, and distribute this software **and its** > * **documentation** for any purpose with or without fee is hereby granted, > * provided that the above copyright notice appear in all copies and > * that both that copyright notice and this permission notice appear > * in supporting documentation. Full copyright notice here: https://sourceforge.net/p/gnuplot/gnuplot-main/ci/master/tree/Copyright The term “gnuplot license” is not very widespread but brings satisfying results on search engines (including on wikipedia), so I took the liberty to add a link to the copyright file, taken from the “Gnuplot's copyright” link on the gnuplot home page, http://gnuplot.info. Here is how to build the gnuplot docs to parse them: mkdir gnuplot-src gnuplot-conf $DEVDOCS_ROOT/docs/gnuplot git clone -b 5.2.7 --depth 1 https://git.code.sf.net/p/gnuplot/gnuplot-main ./gnuplot-src cd gnuplot-src/ ./prepare cd ../gnuplot-conf ../gnuplot-src/configure make -C docs nofigures.tex latex2html -html 5.0,math -split 4 -link 8 -long_titles 5 -dir $DEVDOCS_ROOT/docs/gnuplot -ascii_mode docs/nofigures.tex

CICimbali committed 7 years ago