Several changes.. see description

Desktop-Side:
QRFrame: Option to disable loopback-ip-address (default is disabled)
Dealt with GUI-Issues. Better, but not perfect. Removed all warnings on
desktop-side.
Removed old (unused) main window

Android:
Changed to min-sdk 10.
Removed settings (not totally, only call to settings)
Added Dialog to ask user if presentation should be removed when closing.
Removed old buttons (Exit, download, settings)
Removed warnings.