merged @dpvc's updates to v2.3-latest into master
merged @dpvc's updates to v2.3-latest into master

mathjax/MathJax-docs,mitya57/mathjax-docs,mitya57/mathjax-docs,GerHobbelt/MathJax-docs,Axure/MathJax-docs,Axure/MathJax-docs,GerHobbelt/MathJax-docs,mathjax/MathJax-docs