Improvements for screen orientation changes

- Adding alternative layout for landscape mode.
- Overriding activity's onSaveInstanceState method to store question index so app remembers question index after user changes screen orientation.
- Adding some logging to show activity lifecycle events.
- Updating Android target to v4.2 (instead of 4.4) as changing screen orientation in emulator didn’t work when pressing ctrl+fn+f12. Google searches imply it’s a bug with KitKat.