Adjust logging rate based on the DetectedActivity API

[kuro68k]

The DetectedActivity API allows the app to respond to changes in activity, like going from sill to walking, or getting in a vehicle.

By adjusting the logging rate based on the current activity, significant battery savings could be made for people who like to keep logging for long periods of time.

https://developers.google.com/android/reference/com/google/android/gms/location/DetectedActivity

[GrazianoCapelli]

Unfortunately we cannot use the DetectedActivity API because it is part of Google Play Services: we chosen to make an app that doesn't depends on any of them.
Anyway, we could implement an automatic logging adjustment basing on the type of activity, that could be detected basing on speed and other GPS information (the app already implements a basic activity recognition algorithm).

[kuro68k]

Thanks @GrazianoCapelli. Any implementation would be good. Maybe you could also use the device accelerometer to detect one of the most common situations where updates are unnecessary: the device is still, e.g. sat on a desk.