This update for xfce4-clipman-plugin fixes the following issues:

Update to version 1.6.4

* history-dialog: Fix memory leak
* history-dialog: Keep paste-on-activate in sync with the settings
* history-dialog: Remove useless creation/destruction of menu
* Simplify main app creation
* history-dialog: Better fit with the way GApplication works
* settings: Remove wrong signal handler
* settings: Better fit with the way GApplication works
* popup-clipman: Enable translations
* popup-clipman: Properly use GApplication
* Move default clipboard restoration from manager to collector
* gsd-clipboard: Add missing sanity check
* Remove dead code
* menu: Add some icons
* history: Clear history when it's disabled
* menu: Shift entries in reverse order
* Revert "Enable reverse-order option"
* menu: Improve management of clear history entries
* menu: Improve management of primary clipboard entry
* history: Refactor item_to_restore into image_to_restore
* settings: Align paste-on-activate combo like other widgets
* collector: Properly sync primary clipboard when default is empty
* collector: Fix primary timeout management
* collector: Remove unused function
* Make 'add-primary-clipboard' management internal to the collector
* Make 'add-primary-clipboard' imply 'persistent-primary-clipboard'
* settings: Fix 'skip-action-on-key-down' sync and improve strings
* collector: Make actions work again for selections
* collector: Fix memory leak
* collector: Properly disconnect signal handlers
* gsd-clipboard: Properly reset source id
* menu: Fix crash when selecting QR code
* Remove XfcePluggable from settings desktop file
* build: tests: Fix compiler warnings
* Translation Updates