This commit adds a new hook `org-src-mode-hook'.
The Hook run after Org switched a source code snippet to
its Emacs mode. This hook will run
- when editing a source code snippet with \"C-c '\".
- When formatting a source code snippet for export with htmlize.
You may want to use this hook for example to turn off `outline-minor-mode'
or similar things which you want to have when editing a source code file,
but which mess up the display of a snippet in Org exported files.
Carsten Dominik