Improve default group and user icon
Improve icons for default user, group
Update email_id cache when user has registered
Enable adding group member when email service is not available.
Added missing import
Added account type
some more german translations, have been missing in 1.6.1

more translations to german
Merge branch 'master' of github.com:HenriWahl/seahub

Conflicts:
	locale/de/LC_MESSAGES/django.po
more german translations