Improved projector zoom and scroll behaviour.

Zoom and scroll the full content div (incl. title and sidebar).
Add zoom and scroll level in projector live view widget.
Fixed portable build error for pillow package. Updated create_portable.txt.
Add message if someone adds himself to the list of speakers. Fix #927.
Fixed #948: Use DIN A4 format and wlan ssid qrcode on access data PDF.
Merge pull request #952 from emanuelschuetze/zoom

Improved projector zoom and scroll behaviour.
Merge pull request #953 from emanuelschuetze/portable-fix

Fixed portable build error and updated create_portable.txt
Merge pull request #954 from emanuelschuetze/password-pdf

Use DIN A4 format and wlan ssid qrcode on access data PDF
Merge pull request #955 from normanjaeckel/Fix927

Add message if someone adds himself to the list of speakers. Fix #927.