Bluetooth plugin is broken on Android 6
Android 6 no longer allows access to the local Bluetooth address. BluetoothAdapter.getAddress() now returns a fixed value. This will break our ability to give our address to contacts so they can connect without performing discovery.
The plugin still uses BluetoothAdapter.getAddress(), it's only TestingActivity and CrashReportActivity that look at the value in Settings.Secure. we need to add a method (maybe in AndroidUtils?) for getting the value from the adapter, checking whether it's valid, getting the value from Settings.Secure if it's not, and throwing an exception if there's not a valid address there either.