title: react-navigation stack navigation without initial screen? (from a button)
body: <p>We are using a different router for our app (react-router)</p>
  <p>We are integrating react-navigation in some screens of our app.<br />
  (For example, we can adapt react-navigation for user profiles related screens)</p>
  <p>Now, we have new requirements, where we want to use react-navigation from a button of an existing screen (which is not part of react-navigation)</p>
  <p>Say you have a screen where there is a button which will create a new screen (stack a new screen). I want the navigation from the existing screen to new screen handled via react-navigation.</p>