I18n: Update translation ca (100%).

113 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
Remove unneeded files.
I18n: Update translation pl (100%).

113 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation en_GB (100%).

113 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Add new translation en_AU (100%).

113 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation fr (100%).

113 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).