MapEver photo map

Mar 21, 2022

WARNING: RISK FOR DATA LOSS
All map names will be lost!
You will not be able to move back to a previous version without losing map data, so make a backup!

This is due to code changes that will ease future development (however much that may be).

Other changes:
- support Android 11 (try deleting sdcard/emulated/0/mapever directory)
- make it possible to rotate maps
- much faster map rendering on multicore devices
- general code improvements
- support and require newer Android versions