Corrected a test that used the wrong copy "constructor".
Activity can now give the names of its resources.
Tests for activities with and without participants.
userMock now accepts a user on construction.
Added tests for activity page when a user is logged in.
created a mixin for the developer count
created another mixin for the subscription buttons.
Now the subscription links contain the  resource (which is ignored for now...)
Activities can now add/remove participants to/from a given resource (if it is present).
Activity.registeredMembers must cope with nonexistent resources.
First (ugly) attempt to display a button for each resource. Does not yet render resource labels.
First optical improvements for activity page with multiple resources.
Merge commit '829d4ef4586917e516aff276492dfb133de1f6d5'
Adapted tests to latest design changes (ouch...)
Merge pull request #452 from NicoleRauch/master

Die Aktivitäten-Seite kann jetzt mit mehreren Ressourcen umgehen.