Added MathJax

Hi Bill,

  So I thought I'd add in the JavaScript necessary to load up MathJax so that the abstracts that contain TeX-formatted math will be displayed appropriately. Should also work for comments that wish to contain maths.

  Note: I've not tested this, because I don't know much about running ruby-on-rails, but I think the place I added it is the correct spot (or at least a spot that will result it being in the header of the document), so it should work.

  Let me know if there is a better place to put it (or if you don't want this on scirate for some reason).

--
Noon