title: Override onLeft and onRight handlers in react-native-router-flux
body: <p>I found how to override the onLeft and onRight handlers for the buttons in the NavBar with <code>react-native-router-flux</code> inside my component. So when I <code>console.log()</code> in there I see the output. However, I cannot seem to find a way to pass props (and thus my state) into there.</p>
  
  <p>I cannot access them via <code>this.props</code> since they are required to be static methods. Any idea? I just want to dispatch an action but I need the <code>dispatch</code> function which is not available inside the handlers (I am using <code>redux</code>)</p>
  
  <pre><code>class ProfileSettings extends Component {
    static rightTitle = "Save";
    static onRight(...props) {
      console.log('right!') // logs 'right' when pressed
      console.log(props)    // logs an array of the connect function (react-redux) + an empty object
    }
  </code></pre>
  
  <p>Thanks!</p>