- Add per-panel setting icon-size
- Set minimum Gtk+3 version to 3.22
- Bugfixes:
  - Gtk+ deprecation fixes (all plugins)
  - tasklist: Fix group-button states
  - libxfce4panel: arrow button size fixes
  - launcher: plugin sizing fixes
  - appmenu: Add support for other menu editors (Bug #11684)
  - tasklist: Fix urgency blinking for group buttons (Bug #6904)
  - tasklist: Add 'group-button' styleclass
  - Fix anchors for gtk_menu_popup_at_widget (Bug #14803)
  - Fix struts on the bottom and right of the screen (Bug #14886)
  - tasklist: Don't listen for monitor changes in the plugin (Bug #10725)
  - tasklist: Use Gdk to to determine which monitor contains a window
  - tasklist: Ensure pressed buttons with open menus
  - tasklist: Replace exo-lucency with gtkcss
  - tasklist: Make all-minimized group buttons translucent (Bug #10862)
  - tasklist: Switch from wnck* icons to standard names
  - tasklist: Keep groupbutton active after closing menu
  - tasklist: Make sure icons in the group menu are 16px
  - tasklist: Make grouped buttons active (Bug #9129)
  - launcher: Rely on icon-size provided by panel
  - Prevent crash on removing certain plugins (Bug #14418)
  - Add configure button to composited infobar
  - Make compositor info in settings dialog a GtkInfoBar
  - directorymenu: Fix crash and drop deprecated call
  - Fix unreadable panel items without compositing (Bug #14842)
  - launcher: Fix arrows not being shown (Bug #14373)
  - launcher: Fix tooltip icon size (Bug #14774)
  - Re-introduce button images to plugin settings dialogs
  - Make the settings dialog more HIG compliant
  - launcher: Add 'New Link' button to properties (Bug #14855)
  - Drop the panel's welcome dialog (Bug #14388)
  - clock: Resolve deprecations and fix binary clock
  - Workaround for xinput2's subpixel handling (LP #1795135)
  - Ensure the orientation style classes are always applied
  - Add orientation-related style classes for improved theming
  - actions: Add support for dm-tool
  - panel-window: set struts with monitor scaling
-Translation updates: Albanian, Arabic, Asturian, Basque, Belarusian, Bengali,
  Bulgarian, Catalan, Chinese (China), Chinese (Hong Kong), Chinese (Taiwan),
  Croatian, Czech, Danish, Dutch (Flemish), English (Australia), English
  (Great Britain), Estonian, Finnish, French, Galician, German, Greek, Hebrew,
  Hungarian, Icelandic, Indonesian, Italian, Japanese, Kazakh, Korean, Lithuanian,
  Malay, Norwegian Bokmål, Norwegian Nynorsk, Occitan, Panjabi, Polish,
  Portuguese, Portuguese (Brazilian), Romanian, Russian, Serbian, Slovak,
  Slovenian, Spanish, Swedish, Telugu, Thai, Turkish, Ukrainian, Uyghur,