title: How do I access a prop passed to TabNavigator within tab screen?
body: <p>I have a tabnavigator like so</p>
  
  <pre><code>var TabNavigation = createBottomTabNavigator({
      NearbyScreen: { 
          screen: Nearby
      },
      FindScreen:{
          screen: LandmarkNavigation
      },
      NotificationScreen:{
          screen: Notifications
      },
      MyProfile:{
          screen: MyProfile
      }
  })
  </code></pre>
  
  <p>that is rendered in the component </p>
  
  <pre><code>render() {
          //console.log(this.props);
          var nearbyLocations = this.props.locationsNearby;
          return(
              &lt;TabNavigation thisThing="thisThingValue" /&gt;
          )
      }
  </code></pre>
  
  <p>How do I access the value of the prop I passed on  inside one of it's tabs?</p>