This patch adds a fourth 'native value to
org-highlight-latex-and-related. It matches the same structures than
'latex but it calls org-src-font-lock-fontify-block instead.

It's a simple change that brings full latex fontification by building
on top of org-src. I'm using it (implemented as an advice) since a few
weeks ago and haven't noticed any problem.

Hope you like the idea.

Best regards
--
Carlos