Currently when you're on the main app screen (the dive carousel) and press the back button nothing happens. This isn't generally consistent with the default behaviour you'd expect on Android (you'd expect it to either exit the app or less commonly prompt you to confirm exiting the app).
This PR changes the behaviour to make the back button exit the app from the main screen. Also fixes a file format exception on the DB load.
Currently when you're on the main app screen (the dive carousel) and press the back button nothing happens. This isn't generally consistent with the default behaviour you'd expect on Android (you'd expect it to either exit the app or less commonly prompt you to confirm exiting the app).
This PR changes the behaviour to make the back button exit the app from the main screen. Also fixes a file format exception on the DB load.