Don’t select-frame after Babel export

[Titus von der Malsburg]

When I export an org document to PDF via Babel, the frame is select at the end 
of the process.  Is there a way to prevent this?

Example:

1. Request exporting the following org file to PDF via `C-e C-p`:

  This is a test:

  #+BEGIN_SRC elisp :eval yes :exports both
  (sit-for 3)
  (print "Done!")
  #+END_SRC

2. Then immediately iconify the Emacs frame.
3. Wait until the end of the 3 seconds.
Result: The Emacs frame will be raised and focused.

Background: I often export computation-heavy org documents and work on 
something else in the meantime.  I don’t want Emacs to interfere with that 
other work when it’s done exporting.

  Titus