4.15.0

- Use icons from icon theme in the dialog (!3)
- Add new app icon and switch to rDNS
- Remove PDA tab (!1)
- Avoid critical error when closing preferences dialog
- Support libxfce4ui XfceTitledDialog new API
- Translation Updates:
  Albanian, Belarusian, Bulgarian, Chinese (China), Chinese (Taiwan),
  Croatian, Danish, Dutch, Eastern Armenian, English (United Kingdom),
  Estonian, Galician, Greek, Hebrew, Hungarian, Indonesian, Interlingue,
  Italian, Japanese, Lithuanian, Portuguese, Russian, Slovenian, Spanish