Note that this is currently untested. :o

Feedback is stored in memory on the server, and not inside
CouchDB any more.

With this patch all feedbacks will be stored in memory without any
interaction with CouchDB. Due to in memory storage, all feedbacks will
be removed if server gets restartet.

Depending on new requests, feedbacks will be deleted after some time. 

question object.

saveQuestion, update(Question), getAnswers, saveAnswer, getMyAnswer.

This should perform much better.

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.