Pixbuf loader should not use rsvg_handle_set_size_callback
Submitted by Christian Persch
rsvg_handle_set_size_callback is used in rsvg-view, rsvg-convert, and the pixbuf loader . Should port these to just using a cairo transform. Also, rsvg-view and rsvg-convert use _rsvg_size_callback as the handler to rsvg_handle_set_size_callback, which is an internal function of librsvg; it should be unexported from librsvg then.