pretty export xml

[Philippe Faes <Philippe Faes UGent be>]

How can I make Dia export human-readable XML? I know how to set it so
that it doesn't compress the files, but all the data is in one line (no
'\n' characters, no indentation). I remember dia used to save its files
"nicer". Maybe this should be the default. I don't thing we save a lot
of disk space by leaving these TAB and EOL characters out.

-- 
grtz
PhF