Remove invalid translation.
I18n: Update translation pl (100%).

75 translated messages.

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

75 translated messages.

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

75 translated messages.

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

75 translated messages.

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