TeX typography support

\TeX ~typography support is enabled on the website. \begin{equation} \label{beta} \beta=(X'X)^{-1}X'Y \end{equation} It can be used in comments, in forums, in news, group pages and so on. Combined with the revision control system, already available on NES Alumni and Friends website, and the Page content element this allows to publish favorite formulas and create multi-author \LaTeX~documents in wiki-style. That is --- users will be able to see which changes were introduced by which user; they will be able to compare different versions of the same document, and roll back to previous versions if needed.