Changed PDF::Stream to use an ostream rather than a homebaked add_string aproach for appending content to the stream.  This leads to simpler / nicer code as well as to faster execution.
Changed PDF::Stream to use an ostream rather than a homebaked add_string
aproach for appending content to the stream.  This leads to simpler /
nicer code as well as to faster execution.

GNOME/passepartout,GNOME/passepartout,GNOME/passepartout,GNOME/passepartout