beta updates

[Dirk Hohndel]

I pushed a new version to the beta channel on Google Play, and of course
it's also on downloads/test

- AppLog is now stored as subsurface.log (most likely in the root of your
  emulated storage)
- libdivecomputer log can be enabled and is stored as libdivecomputer.log
  in the same location
- bug fix for Scubapro G2 BLE download
- better information on the download from DC page, no more confusing "one
  empty dive" - instead we show the progress info that libdivecomputer
  gives us.

All in all, a significant step forward.

Thanks

/D