Open MainUI 1.0.1

A reliability and compatibility release. It is recommended for everyone on 1.0.

Highlights

• Your language is used from startup. In 1.0, labels stayed in English until a language was chosen again in Settings, and again after every game.
• Theme backgrounds are the right way up. Onion stores background.png upside down; 1.0 showed it as stored. This affected many themes. (#1)
• A damaged or unusual SD card no longer stops the launcher. An unreadable Emu folder, a bad console or app config.json, missing theme fonts, an unreadable Favorites or Recents file, or an unusable theme path now falls back gracefully and logs the reason. (#5)
• ROMs larger than 2 GiB (for example multi-disc PBP files) are no longer treated as missing. (#2)
• Launching a game no longer fails when the list position cannot be saved, and a damaged romwinidx.json is replaced. (#3)

Also in this release

• Fallback fonts follow the language as in stock, and MainUI restarts itself when a language change needs a different fallback font.
• Settings are no longer reported as failed when the file was saved but flushing the card failed.
• Folder scans no longer follow symlinks. FAT cards are unaffected.
• Test wrapper: logging problems never block startup. (from #4)
• New guide for theme authors: docs/THEMES.md

See CHANGELOG.md for the complete list.

Thanks

Special thanks to @Amiga500 for the detailed startup report and repro script (#5), and for the fixes in #2, #3 and #4. That report started the sweep that led to most of this release. Thanks also to everyone who tested and reported issues.