Add German translation

This adds a German translation for the theme.
Set correct language in German Translation

Set the po file entry "language" correctly"
Fix translation of "Published" at article bottom

This will show the translated string for „Published“ at the bottom of
an article.
Add audio post format support. Fixes #140
Don't show taxonomy stats when using Infinite Scroll. Fixes #110
Fix bug where new unapproved comment appeared hidden. Fixes #119.
Update default language files
Update default langauge files (adds missing 'Published' string)
Update German language files to the latest changes
Merge pull request #137 from JHillert/master

Add German translation