Easy xkcd

Invalid date

- Fix crash during database migration
- Use BottomAppBar instead of NavigationDrawer
- Comic database is now built dynamically, no more "loading database" dialogs!
- "Explain Comic" button is now displayed as an icon if there's enough room in the toolbar
- Scroll position in WhatIf articles is now persisted on rotation
- Add animations in overview when toggling "hide read" or "favorites"
- Lots of bug fixes and stability improvements