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'
This adds an option to select the preferred clock to show on the
main screen.
The settings app menu lists all apps of type 'clock' with the
current one marked with a *. It stores the src property
of the selected clock as settings.clock.
The bootloader app checks this property and tries to load
that app. If the property is not set, or the app not found
then it reverts to the current behaviour of using the first
clock app it finds.