General:
- Add gi.require_version('Gtk', '3.0') to silence warning
- Add appdata file and install (LP: #1554273)
- Add .bzrignore
- Add "Xubuntu Bionic" layout, rename old Xubuntu layouts to "Xubuntu Precise" and "Xubuntu Trusty"
- Drop unused properties from the various layouts
Bugs Fixed:
- Added error handling for failed backup file parsing
- Update categories to display in Xfce Settings Manager (LP: #1734516)
- Improve restoration of saved templates (LP: #1575996)
- Move supported save and load commandline parameters to the main binary (LP: #1556737)
- Backup current configuration at startup so it can be rolled back (LP: #1555265)
Updated translations: Brazilian Portuguese, Czech, French, Galician, Italian, Kazakh, Polish, Slovenian