Feature progress

[philj56]

Keeping track of various features people have requested, in rough priority order:

• [x] Turbo Toggle
• [x] Save deletion
• [x] Controller remapping
  • [x] Extra screen with arbitrary button support
• [x] Cheats
• [x] Option to toggle whether requestAudioFocus() is called on game start
• [ ] Button labels
• [ ] Warn when importing saves for games that have autoresume enabled
• [x] Game-specific shortcuts on home screen
• [ ] Per-game button layouts
• [ ] Second file browser for external storage
• [ ] Changeable screen size
• [x] GB Camera image exporter (covered by printer support)
• [ ] FAQ / Guide somewhere in settings or home screen