title: scrollTo is undefined on animated ScrollView
body: <p>When using <code>Animated.createAnimatedComponent(ScrollView)</code> to create an animated <code>ScrollView</code> it's not longer possible to use <code>scrollTo</code>.</p>
  
  <pre><code>const AnimatedScrollView = Animated.createAnimatedComponent(ScrollView);
  
  &lt;AnimatedScrollView ref={(ref) =&gt; this.list = ref}&gt;
    &lt;View style={{height: 1000}} /&gt;
  &lt;/AnimatedScrollView&gt;
  </code></pre>
  
  <p>Calling <code>this.list.scrollTo({x: 0, y: 0})</code> gives the following error:</p>
  
  <p><code>_this.list.scrollTo is not a function</code></p>
  
  <p>It works fine on a normal ScrollView. Is there any way to solve this?</p>