Merge branch '225-bluetooth-address' into 'master'

Show Bluetooth address from Settings.Secure in TestingActivity

* To help with investigating #225 (and maybe other bugs in future), show the Bluetooth address from Settings.Secure as well as the address from BluetoothAdapter.getAddress()
* Add Settings.Secure.ANDROID_ID to the entropy pool - it may provide up to 64 bits of extra entropy from the perspective of a remote attacker (no extra bits from the perspective of a local attacker in the same user account, who sees the same ANDROID_ID)


See merge request !73