-- printing: print-to-PDF? (with & without pdf background to merge)
- opacity issue for highlighter strokes (maybe print them below ?)
- save gnome printer settings (throughout a session, and on disk)
- (maybe a separate config file .xournal/gnome-print-settings)
-- file print-options, own print-to-ps/pdf
+- printing: print-options, save printer settings (throughout a session,
+ and on disk) (maybe a separate config file .xournal/gnome-print-settings)