MathJax macros: EPUB and PDF export

[richard015ar]

As a book collaborator, I would like to be able to export PDF and EPUB books with MathJax macros applied and see the formulas as I see them in the web book format.

Depends on #129

DoD:

• Apply necessary changes to export MathJax formulas with macros to PDF and EPUB.

[richard015ar]

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