I18n: Update translation es (100%).

216 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation zh_CN (95%).

207 translated messages, 9 untranslated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).
I18n: Update translation de (80%).

173 translated messages, 43 untranslated messages.

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