Added comment to org-babel-process-result explaining

Added comment to org-babel-process-result explaining
results-processing changes and state they are currently in. Here's the
comment:

  You can see below the various fragments of results-processing
  code that were present in the language-specific files. Out of
  those fragments, I've moved the
  org-babel-python-table-or-results and
  org-babel-import-elisp-from-file functionality into the
  org-babel-*-evaluate functions. I think those should only be
  used in the :results value case, as in the 'output case we are
  not concerned with creating elisp versions of results.

  The rest of the functionality below, concerned with vectorising
  or scalarising results is commented out, has not yet been
  replaced, and may need to be reinstated in this function