Add german translation (#536)

* add german translation

* add german to language list

* donttranslate language names. always use the native name.

* add compiled german translation file

* german translation handling

* add german to getSuffixFromLanguage

* update german string and translation

* update all language files with new strings

* typo

* compile

* more typos and fixes for german

app/settings/streamingpreferences.cpp

@@ -181,6 +181,8 @@ QString StreamingPreferences::getSuffixFromLanguage(StreamingPreferences::Langua
 {
     switch (lang)
     {
+    case LANG_DE:
+        return "de";
     case LANG_EN:
         return "en";
     case LANG_FR: