literal haskell mode (nice :)

[Jorge Adriano]

> I got some tips from some people at #xemacs in openprojects.org and cam up
> with the file in attachment. I know nothing about e-lisp so beware!!

Last e-mail today. Forgot to actually tell what was this for (need ti get 
some sleep :)... It's easy to guess by looking at the file anyway the idea is 
to change xemacs modes acording to context. I changed the orginal file to 
work with literate haskell + latex. It works (for me at least) with the 
\begin{code} \end{code} kind of lhs files.

J.A.