Equation References and Numbering are not going to be trivial to add,
so the code has been removed for now. Important fixes include
no-MathJax support (previously, the code was failing), and the
generation of unique ids for the rendering content in each cell,
tremendously speeding up MathJax rendering.
I am still not rendering placeholder text.
MathJax.InputJax.TeX.resetEquationNumbers is supposed to be available,
but isn't consistently loaded before the notebook fires off its first
re-render request. The code edits in mathjaxutils.js fix this issue.
Additionally, there was some init code in mathjaxutils.js that has been
properly excised to the html templates.
Removed some orphan rendering code so that all typesetting now goes
through mathjaxutils.js
Finally, removed an extra cell in the demo notebook.
