title: Back header button in drawer navigation
body: <p>How can i have a back button on some screen eg ProfileScreen/ReporterScreen such that clicking on it would take user to ContentFlow.</p>
  <pre><code>const ProfileNavigator = createStackNavigator({ ProfileScreen });
  const ReporterNavigator = createStackNavigator({ ReporterScreen });
  
  const ContentNavigator = createMaterialBottomTabNavigator({ ContentScreen });
  
  const HomeNavigator = createDrawerNavigator({
   ContentFlow:ContentNavigator,
   ProfileFlow:ProfileNavigator,
   ReporterFlow:ReporterNavigator
  });
  </code></pre>
  <p>I have added header button for drawer in ContentScreen, but for other screens i want to have back button instead, how to navigate to ContentFlow, when back button is pressed.</p>