Log Message:
xfce4-dict: update to 0.8.4

Change log:

0.8.4
======
- Update URLs and use https where possible
- Fix font size in speedreader (#3)
- Added new icons and use reverse DNS file names
- Translation Updates:
  Albanian, Arabic, Armenian (Armenia), Basque, Belarusian, Bulgarian,
  Catalan, Chinese (China), Chinese (Taiwan), Croatian, Czech, Danish,
  Dutch, Eastern Armenian, English (Australia), English (United Kingdom),
  Estonian, Finnish, French, German, Greek, Hebrew, Hungarian, Icelandic,
  Indonesian, Italian, Japanese, Kazakh, Korean, Latvian, Lithuanian,
  Malay, Norwegian Bokmål, Occitan (post 1500), Polish, Portuguese,
  Russian, Serbian, Slovak, Slovenian, Spanish, Swedish, Thai, Turkish,
  Uighur, Ukrainian, Urdu, Urdu (Pakistan), Vietnamese