IMPORTANT: (possibly) incompatible Change

[Carsten Dominik <carsten.dominik@gmail.com>]

Dear all,

I have just checked in an important change - if you use LaTeX
export, you need to be aware of it.

1. Org contains now a much better system for handling special entities
    that are written like LaTeX macros, for example \therefore,  
\emptyset,
    etc.  I will write more about this in the release notes for 6.35.   
But
    already now thanks go to Ulf Stegemann without whom this would not
    have happened.

2. I could no longer keep the old setup for LaTeX export in
    org-export-latex-classes.  The disadvantage was that whenever you
    needed to make changes to the header, you would fix the value of  
this
    variable so that any changes I'd make in the future would not be  
visible
    to you.

    The way this is solved now is (excerpt from the upcoming release  
notes)

-----------------------------------------------------------------------------
* =org-export-latex-classes= no longer should be customized for packages

The HEADER part of this variable should now only contain the
documentclass macro, nothing else - at least normally.  All the
package calls via usepackage should go into
org-export-latex-packages-alist.  I moved all the default packages
that into a new variable org-export-latex-default-packages-alist.
This will allow me to add more packages (as needed) in the
future, withour requiring you to erase and then redo your
configuration of org-export-latex-classes.

So if you have customized this variable, please remove once more
(hopefully for the last time) your customization, so that it can
revert to its now much simpler default value.  Put all your
package definitions into org-export-latex-packages-alist.
I hope this works, and we will not get conflicts because of the
sequence in which packages are called.  If there are problems,
please let me know so that we can find a solution.
-----------------------------------------------------------------------------

I have not yet put this onto the master branch, but I will soon.
If you want to help testing this new setup, please check out the branch
new-entity-support from the git repo and let me know if you run into any
problems.

Thanks!

- Carsten (and Ulf)