New Bangle.js firmwares remove 8 char name restriction so we're ditching the first char -> file type and using normal file extensions
Took the opportunity to remove code for older Bangle.js (since the new stuff won't work anyway)
Also removed the need for an 'app.json' - it's now renamed 'app.info' on the watch, and we just auto-generate it
Renamed a few apps so widgets all start with 'wid'