po: update cs.po (from translationproject.org)
po: update fr.po (from translationproject.org)
po: update vi.po (from translationproject.org)
po: add hr.po (from translationproject.org)
po: merge changes

Signed-off-by: Karel Zak <kzak@redhat.com>
docs: update AUTHORS file

Signed-off-by: Karel Zak <kzak@redhat.com>