title: Toggling a drawer from header icon using react-navigation
body: <p>I am new to react-native and react-navigation.
  Required Screen: A home page with a header (Thumbnail + title) , two tabs and a drawer that toggles onPress of the thumbnail.</p>
  
  <h2>Please check my code:</h2>
  
  <pre><code>import React, { Component } from 'react';
  import { Platform,  StyleSheet,  Text, View, TouchableOpacity} from 'react-native';
  import {Icon, Button} from 'native-base';
  const util = require('util');
  import { TabNavigator, StackNavigator, DrawerNavigator, NavigationActions } from 'react-navigation';
  import FirstScreen from './tabs/FirstScreen';
  import SecondScreen from './tabs/SecondScreen';
  import Profile from './Profile';
  import SearchScreen from './tabs/SearchScreen';
  
  const DrawerScreens = DrawerNavigator({
      Profile: {screen: Profile}
  },{
      drawerPosition: 'left',
      drawerWidth: 150
  });
  
  // A drawer navigator
  
   const TabScreens= TabNavigator({
      First: {screen: FirstScreen},
      Second: {screen: SecondScreen}
    }); 
  
  //   Started with a tab navigator to register two tabs
  
    const MenuButton =({navigation})=&gt;{
     return(
          &lt;View&gt;        
          &lt;TouchableOpacity onPress={()=&gt;(navigation.navigate('DrawerToggle'))}&gt;
              &lt;Icon name="person" size= {20}/&gt;
          &lt;/TouchableOpacity&gt;
        &lt;/View&gt;)};
  
  export const StackScreens= StackNavigator({
      Draw: {screen: DrawerScreens},
      // Drawer navigator as a screen
      Display: {screen: TabScreens, 
          // Making the tabnavigator as a screen
          navigationOptions: ({navigation})=&gt;({
          title: 'Welcome',
          headerLeft: &lt;MenuButton navigation={navigation} /&gt;
        })
      },
  
  },{
      initialRouteName: 'Display'
  });
  </code></pre>
  
  <hr>
  
  <p>On pressing of the thumbnail the TabScreens navigates to the DrawerScreens (since that is how i coded). I want to make it toggle. Can someone please help me.</p>