Added missing strings in de.yaml

Added 1.6.x strings that were missing
added missing strings, fixed one typo
Added missing 1.6.x strings to de-informal

Added a lot of missing strings, now complete and in sync with master
Finalizing 1.6.x update

Changed messages_what to better fit column.
Updated outdated strings
Consistency in translation of "member"

Make translations affecting members more consistent. Thanks maxx!
Merge pull request #39 from felics/master

Added missing 1.6.x strings, CP fully translated