title: Stop Google Play Services from automatically signing in on app start
body: <p>I've implemented Google Play Services in my app to have leaderboard.</p>
  
  <p>Problem is that they ask user to sign in with their Google account every time when user starts the app (if they are not already signed up), which can be annoying.</p>
  
  <p>Is there a way to stop this? I want to start sign in only when user clicks on 'Sign in' button.</p>