API specification.
Changed StatisticsController to allow requests without a trailing slash
to be consistent with the other **/statistics paths.

API specification.

getInterposedQuestions for .../{questionId} path and renamed method to
singular form.

If the current session is linked to a course and there are other sessions
for this course, add a number to the name and short name of the session,
indicating which session is ment since all sessions will have the same
name and short name.

This fixes Socket.io not broadcasting and accepting feedback data.

/questionbylecturer/* => [/session/{sessionKey}]/lecturerquestion/*
/questionbyaudience/* => [/session/{sessionKey}]/audiencequestion/*

Clean up service tests and clean up logged in users. Added logged in users
if needed.

compatibility with third party frontends.

API changes:
- /session/visitedsessions => /session/?filter=visited
- /session/mysessions => /session/?filter=owned
Added changed routes to LegacyController.

The method now returns users visited sessions and all sessions connected to
a course the user is enlisted - if connector is activated.

If connector is enabled, user will see in addition to his visited sessions
all sessions linked to his courses.