title: react-native-elements icons not showing
body: <p>React-Native-Elements icons showing as (?)</p>
  
  <p>What am I doing wrong? The code looks nearly identical to the sample that they provided on their site.</p>
  
  <p>This is what I see (don't mind the middle icon, it's brought in differently):<br/><br/>
  <a href="https://i.stack.imgur.com/bxbzi.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/bxbzi.png" alt="enter image description here"></a></p>
  
  <p>Code that I'm using for the left icon:</p>
  
  <pre><code>&lt;Icon name='users' type='Feather' size={25} color={tintColor} /&gt;
  </code></pre>
  
  <p>Code for the right icon:</p>
  
  <pre><code>GamesInProgressTab: {
      screen: GamesInProgressNavigator,
      navigationOptions: {
      title: 'Games',
      tabBarIcon: ({ tintColor }) =&gt; ( &lt;Icon name='rocket' type='Entypo' size={25} color={tintColor} /&gt; ),
      }
  } 
  </code></pre>