etherpad: fix error if no last edit time is set
etherpad: Use unicode_literals from __future__ in views
mail: Use signal to collect mailaddresses
mailinglist: New mailinglist application
mailinglist: Do not add prefix if it already exists
mail/mailinglist: Put all mailservers into one daemon
mail: Add cloak server which hides a users email address
groups: Add GroupProxy.is_admin(user)
groups: Add GroupProxy.is_member(user)