title: TabNavigator extra padding
body: <p>How to style the TabNavigator Tab's height and padding? Im doing the following: </p>
  
  <pre><code>import Icon from "react-native-vector-icons/MaterialIcons";
  const tabNav = TabNavigator({
    TabItem1: {
        screen: MainScreen,
        navigationOptions: {
            tabBarLabel:"Home",
            tabBarIcon: ({ tintColor }) =&gt; &lt;Icon name={"home"} size={20} color={tintColor} /&gt;
        }
      },
      TabItem2: {
        screen: MainScreen,
        navigationOptions: {
          tabBarLabel:"Home",
          tabBarIcon: ({ tintColor }) =&gt; &lt;Icon name={"home"} size={30} color={tintColor}  /&gt;
        }
      },
      TabItem3: {
        screen: MainScreen,
        navigationOptions: {
          tabBarLabel:"Browse",
          tabBarIcon: ({ tintColor }) =&gt; &lt;Icon name={"home"} color={tintColor} /&gt;
        }
      }
  }, {
      tabBarPosition: 'bottom',
      tabBarOptions: {
          activeTintColor: '#222',
          activeBackgroundColor :'yellow',  //Doesn't work
          showIcon: true,
          tabStyle: {
              padding: 0, margin:0,   //Padding 0 here
          },
      iconStyle: {
          width: 30,
          height: 30,
          padding:0       //Padding 0 here
      },
      }
  });
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/5qjVU.png" rel="noreferrer"><img src="https://i.stack.imgur.com/5qjVU.png" alt="enter image description here"></a></p>
  
  <p>How do I get rid of the padding between the icon and the label? I did <code>padding:0</code> in <code>iconStyle</code> and also in <code>tabStyle</code> but no luck. I want no padding below the <code>label</code> too. How do I do that? Thanks.</p>
  
  <p>Found the extra padding is caused by <code>View</code>: 
  <a href="https://i.stack.imgur.com/FET1S.png" rel="noreferrer"><img src="https://i.stack.imgur.com/FET1S.png" alt="enter image description here"></a></p>
  
  <p>How do i get rid of that?</p>