We’ve had serious problems with local files using indexedDB on Firefox & Safari, and had to switch to CacheStorage. Sorry for your potentially lost backgrounds and black screens everyone

Migrate local files from indexedDB to CacheStorage
Added Help Mode to debug more easily, accessible with CTRL + Shift + ?
Added video credits
Fixes and improvements:
- Fixed folder links duplicating #642
- Fixed broken google search #668
- Fixed background refresh not working while paused
- Improved gist sync error messages #666
- Cleaner local files UI
Translations:
- Added Icelandic by @JonGretar, thanks !
- German small fix by @DanielGilbert
- Russian changes by Shlerspet