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

add feedback messages to communicate w/ backend

Add extraction command

Added extension package for tslint.

Generated angular project 'arsnova-angular-frontend' by angular cli.