Add encoding to the output of p:data

If p:data loads a non-XML file, it will base64 encode that file. I think
that under those circumstances, it should add (c:)encoding="base64" to
the wrapper.

                                        Be seeing you,
                                          norm

-- 
Norman Walsh <ndw@nwalsh.com> | A man is not necessarily intelligent
http://nwalsh.com/            | because he has plenty of ideas, any
                              | more than he is a good general because
                              | he has plenty of soldiers.-- Chamfort