o added 'mathjax_inline' to html options for including the MathJax
    javascript in the HTML document rather than linking to it online.
    This required changing from an HTTPS to an HTTPS MathJax URL.
Changed to use term 'embed' instead of 'inline'.
Merge pull request #44 from HenrikBengtsson/master

Option 'mathjax_embed' for downloading and embedding the MathJax script