Issue/989 expose applog to all users

I checked all AppLog calls and cleaned some (thanks to `ack -B 5 AppLog`), I also assumed:

* it's safe to print the device id returned by our notification manager
* network calls never reply with username/password (we print a few raw network response on error)

I replaced all `printStackTrace()` by `AppLog.e()` and tried to remove some. Refactoring in 1db61c41776a9eeed195df92af5904cce40f5751 and 5370e358805a7c5a93f8aeda2415bc392fc9818a