[O] smart loading languages

[Andreas Röhler]

Hi,

instead requiring explicit

(org-babel-do-load-languages
 'org-babel-load-languages
 '(
   (LANGUAGE-1 . t)
   (LANGUAGE-2 . t)
   ...
   (LANGUAGE-N . t)
   ))

in Emacs init, AFAIU that might be done first time when a source block is 
evaluated.

Andreas