activities can now be created by every member and each member can edit her own activities
Merge branch 'hotfix'

# Via Andreas Leidig (1) and leider (1)
* hotfix:
  Fixing that any superuser can add new authentication to any user
Merge branch 'hotfix'

# Via Andreas Leidig (2) and leider (1)
* hotfix:
  FIX: sent mails don’t render txt on button
  no message
remove hidden field that’s not needed
when saving a newly created member, user’s profile must be deleted to assure reliable (de)serialization of user across sessions
Merge pull request #491 from leider/master

activities can now be created by every member and each member can edit h...
bigger scroll area for admin tables on iPhone
fixing „empty groups show all members as group members“
And here: a test for the fix
Merge pull request #497 from leider/master

one fix + one UI enhancement
fix typo
member list for activities now sorted
now also guests have a link to report bugs - btw. we now call it „feedback“
updated github links
Merge pull request #498 from leider/master

minor enhancements
removed announcements from top menu, added link in the sidebar if more than five
extra test for  sidebar
Every surfer sees the participation links now
do not show feedback button in iPhone displays for registered members
member list now secures itself to not show member details to not registered user