Added latex equations to latex generation, removed from pdf generation

[ngersich]

Connected to issue #727.

• This takes advantage of the DOM parsing to add Latex to Tex files. The raw LaTeX equations are pulled out from the MathML to be included in the TeX file.
• In the case of PDFs, this simply removes the mathML altogether. I created a long writeup in Verify MathML production for equations #727 of the different things I've tried throughout the semester to try to correct the issue. While often close, I was never able to get all the features working that are necessary for INotes (most notably images). I'm not sure if this is something that should be prioritized or is worth the effort to fix.