updated bootstrap-timepicker, removed the css-file as we do not need it
groups test now structural identical to other app tests
admin column must also be removed from sortable columns
Merge commit '91a95efc540a51bc5ee3a721e689b4fa4eec57a1'

Conflicts:
	test/groups/groups_test.js
editing groups now only possible by superusers and contact persons
preparing more tests for mailsenderAPI
improve readability for test assertions of mail sender
now showing the reason of a send error instead of __err__
test for sending reminder for activity
Merge commit '2ef079a8078ba5db689e48fd33a537c1ab980e21'
test for sending invitation for activity
test for sending mail to member
Merge pull request #564 from leider/master

tests for mail sender API