I18n: Remove broken / unsupported translations.

See http://users.xfce.org/~nick/broken-i18n/ for files and logs.

Use https://www.transifex.com/projects/p/xfce/ to upload fixed versions or request a translation team.
I18n: Update translation fr (100%).

170 translated messages.

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

170 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation ug (94%).

160 translated messages, 10 untranslated messages.

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

170 translated messages.

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

170 translated messages.

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

170 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation ca (92%).

157 translated messages, 13 untranslated messages.

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

170 translated messages.

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