add tweaks for new web version release

src/build-web.sh

src/source/_inkscape/make-pngs.sh

src/source/_static/custom.css

src/source/_static/mntstyle.css

src/source/_tex/post.tex

src/source/_tex/pre.tex

src/source/conf.py

src/source/input.rst

src/source/preface.rst

src/source/software.rst