Merge fix for feedback

fix path for feedback view

See merge request arsnova/arsnova-lite!164

use shortId for frontend url
use roomId for subscribing to backend channels

Diagrams for planned comment feature

See merge request swtp-2019/arsnova-lite!8

Add new author

See merge request swtp-2019/arsnova-lite!6

Fix session-creation for guest lecturer

Closes #204

See merge request arsnova/arsnova-lite!163

Add new author

See merge request swtp-2019/arsnova-lite!7

add new author

See merge request swtp-2019/arsnova-lite!5

add name to authors.md

See merge request swtp-2019/arsnova-lite!3

add name to author

See merge request swtp-2019/arsnova-lite!4

update authors

See merge request swtp-2019/arsnova-lite!1

Update authors.md

See merge request swtp-2019/arsnova-lite!2

Basic functionality for an audience response system.

Features:
- Roommanagement
- Different question formats (likert, mc, yes/no, text)
- Statistics on the evaluation of the answers to the questions
- Interactive feedback
- Comments from participants

This version is brought to you by:

Project management: Klaus Quibeldey-Cirkel

Lukas Mauß <lukas.mauss@mni.thm.de>
Tom Käsler <tom.kaesler@mni.thm.de>
hagen.dressler@mni.thm.de
heinrich.marks@mni.thm.de
david.donges@mni.thm.de
lukas.kimpel@mni.thm.de
thomas.lenz@mni.thm.de
lorenz.detterbeck@mni.thm.de

Fix pipeline

See merge request arsnova/arsnova-lite!152

Merge branch '202-follow-up-from-several-fixes' of git.thm.de:arsnova/arsnova-lite into 202-follow-up-from-several-fixes