[Orgmode] MathJax is now the default for HTML math

[Carsten Dominik]

Good morning everyone.

If you do you daily pull today, something important will have
changed in Org-mode.  From now on, the default settings will
use the incredible MathJax library to display math in
exported HTML.  If you had never turned on LaTeX snipped
math publishing, this will now magically work all by itself.

So the default is now

   (setq org-export-with-LaTeX-fragments t)

and it means that MathJax is used.  This is an incompatible change -  
the same
setting used to mean to transform math expressions into png images  
which are
then inlined into the Web pages.

I believe that the MathJax solution is superior in every way, which
is why I am making this change without prior discussion.  If you still
find a reason to go back to the images, you can do so with

   (setq org-export-with-LaTeX-fragments 'dvipng)

or with

   #+OPTIONS: LaTeX:dvipng

The reason why we can make MathJax work without any additional work by
either author or reader is that Bastien has agreed to serve MathJax from
http://orgmode.org/mathjax/MathJax.js.  This is brilliant.  However,
if many people use this, this will put pressure on his server, and we  
have
no idea how big the demand will be as time goes by.  We will have to  
monitor
the resulting server load and see how tis works.  If you are going to  
use
math in webpages frequently or on pages with many views, we are asking
you to install your own version of MathJax on your server - it is as
simple as unpacking a zip file.  Detailed instructions will be posted
on Worg some time soon.

If you have your own installation, or if you want to configure other  
aspects
of MathJax, take a look at the variable
org-export-html-mathjax-options.

I am really, really excited about this change.  Using MathJax makes  
Org-mode
a tool without peer for scientific note taking, I believe.  It will
also drastically improve the quality of printed web pages, because
the web pages will not use fixed-resolution images, but scaleable fonts.

- Carsten