Default style to absoluteFill

Since the Lottie React Native improvements to scale type in
1629e0e, the AnimationView can
safely default to absoluteFill and the animation will be rendered
at its original size centered in the view.

Fixes lottie-react-native#136

Author: Gabriel Peal

src/js/LottieView.js

@@ -63,6 +63,7 @@ const defaultProps = {
   loop: true,
   enableMergePathsAndroidForKitKatAndAbove: false,
   resizeMode: 'contain',
+  style: StyleSheet.absoluteFill,
 };
 
 const viewConfig = {