@Override
    public Bundle editProperties(
            AccountAuthenticatorResponse r, String s) {
        throw new UnsupportedOperationException();
    }
Manages "Authentication" to Sunshine's backend service.  The SyncAdapter framework
requires an authenticator object, so syncing to a service that doesn't need authentication
typically means creating a stub authenticator like this one.
This code is copied directly, in its entirety, from
http://developer.android.com/training/sync-adapters/creating-authenticator.html
Which is a pretty handy reference when creating your own syncadapters.  Just sayin'.
app/src/main/java/com/example/android/sunshine/app/sync/SunshineAuthenticator.java