Resolve "Content Auszeichnung"

Closes #156

See merge request swtp-block-ws17/arsnova-angular-frontend!109

Added dialog component that build up a form based on a passed data array
and returns the values in case the form gets submitted.

Add component offering markdown action buttons

Resolve "internationalization"

Closes #160

See merge request swtp-block-ws17/arsnova-angular-frontend!106

Resolve "login/room creator screen bug"

Closes #170

See merge request swtp-block-ws17/arsnova-angular-frontend!105

Add extraction command

Resolve "Feedback Barometer"

Closes #158

See merge request swtp-block-ws17/arsnova-angular-frontend!111