reverting merge in bcdd7f7215eece40ba5c1e39da212a2059c594af, it might have been corrupt, we'll see soon :D
another try... merging 6172b6d03c9e7cd883228b45ada3ba2a6a9d5234...2ace4f2ccf03806a4dbe728754dcccff5c3cbb31 (from 1.0)
syncing changes from source:/branches/dominik-validation-argument-sources@2988