* add -0 for outputting null-terminated list
this doesn't add much, if any, additional complexity to the codebase and
can be quite handy for scripting purposes.
Closes: https://github.com/nsxiv/nsxiv/issues/67
* Fix typo
Co-authored-by: Berke Kocaoğlu <berke.kocaoglu@metu.edu.tr>