4.17.1

- Add xfce_gdk_device_grab
- Fix xfce_gdk_screen_get_active to return correct monitor number
- Switch keyboard shortcut 'tile-up' with 'tile-down' (were mixed up)
- Usage of '&lt;' and '&gt;' instead of '<' and '>' in XML (Issue #44)
- Change "Setting System" to "Settings Manager"
- Add 4.18 section to docs
- Add 4.16 section to docs
- Translation Updates:
  Albanian, Amharic, Arabic, Armenian, Armenian (Armenia), Basque,
  Belarusian, Bengali, Bulgarian, Catalan, Chinese (China), Chinese
  (Hong Kong), Chinese (Taiwan), Croatian, Czech, Danish, Dutch,
  Eastern Armenian, English (Australia), English (United Kingdom),
  Estonian, Finnish, French, Galician, German, Greek, Hebrew,
  Hungarian, Icelandic, Indonesian, Interlingue, Italian, Japanese,
  Kazakh, Korean, Latvian, Lithuanian, Malay, Norwegian Bokmål,
  Norwegian Nynorsk, Occitan (post 1500), Polish, Portuguese,
  Portuguese (Brazil), Romanian, Russian, Serbian, Slovak, Slovenian,
  Spanish, Swedish, Telugu, Thai, Turkish, Ukrainian, Uyghur, Welsh