Version checking, refined speed control
New features:
- Speed control via a vertical seek bar from 1/1 to 1/25 speed.
- The app checks this github repository for an existence of a new release and notifies the user if there is a newer one.
- The user has the option disable this check for the currently installed version, i.e. the app will not check (and ask) again untill a different version (which has this feature) is installed.
- The app does not hang on black screen if the camera permissions are denied but exits gracefully instead.