brought ad hoc conferences back. fixed #688 fixed #367
Merge branch 'development' of https://github.com/siacs/Conversations into development
import fixes
fixed potential NPEs
Update german translations
change status codes string 'number' to a better readable constant.
Merge pull request #699 from betheg/status_code

change status codes string 'number' to a better readable constant.
Merge pull request #698 from kriztan/patch-1

Update german translations