title: Handle Back Button in each scene navigation in react Native
body: <p>I have included the back button as a image in the scene which i want back button, I want to perform the back action in the component, Is it possible?</p>
  
  <pre><code>&lt;Scene key=“Courses”  icon={TabIcon}  iconName=“book” backButtonImage={require(‘./app/icons/back.png’)}&gt;
             &lt;Scene key=“CourseList” component={CourseList}  title=“Courses”  navigationBarStyle={styles.navBarColor} titleStyle={styles.navBarTitleColor} /&gt;
             &lt;Scene key=“levels” component={levels}  barButtonIconStyle={{ tintColor: ‘white’ }} navigationBarStyle={styles.navBarColor} titleStyle={styles.navBarTitleColor} leftButtonIconStyle = {{ tintColor:‘red’}} title=“”/&gt;
             &lt;Scene key=“Units” component={Units} barButtonIconStyle={{ tintColor: ‘white’ }} navigationBarStyle={styles.navBarColor} titleStyle={styles.navBarTitleColor} /&gt;&lt;/Scene&gt;
  </code></pre>