We do not update the published date because some feeds do not contains any date,
in this case it default to time.Now(), which could change the order of items on
the history page.

- Feeds with charset specified only in Content-Type header and not in XML document
- Feeds with charset specified in both places
- Feeds with charset specified only in XML document and not in HTTP header

- added missing String for "Pages Navigation", "Logged as" and "Unread Items"
- fixed some other strings

Since "Next/Previous" are used for switching between single articles and whole pages, the translation has to be more universal. Furthermore unification for Star/Favorites as "Lesezeichen" and items/articels as "Artikel". Some other small fixes.