[O] Latex Preview Equations(with C-u C-u)

[Darlan Cavalcante Moreira]

Recently the latex preview equation in org-mode was improved.
Particularly 'C-c C-c' no longer removes the latex equations overlays,
and now we have a single function, org-toggle-latex-fragment, to
create/remove the image and overlays.

I think these changes were very good. One small inconvenient, however,
is that I usually pass two prefix arguments, 'C-u C-u', to
org-toggle-latex-fragment to render everything in the buffer. If I add a
new equation and then call org-toggle-latex-fragment again with 'C-u
C-u' org-mode will simply remove the overlays. This was not a problem
when there was a single function that only created overlays and another
to remove them.

I think having a 'toggle function' is better, but if the user passes two
prefix arguments he wants to render everything in the buffer, even if
there are already equations overlays in the buffer. Could org-mode be
changed to behave like that?

-- 
Darlan Cavalcante Moreira