Use PorterDuffColorFilter in example in README (#243)

The example now illustrates how the color can be changed without having to implement a ColorFilter (which is non trivial as native code is involved)

README.md

@@ -116,7 +116,7 @@ animationView.cancelAnimation();
 You can add a color filter to the whole animation, a specific layer, or specific content within a layer:
 ```java
 // Any class that conforms to the ColorFilter interface
-final SimpleColorFilter colorFilter = new SimpleColorFilter(Color.RED);
+final PorterDuffColorFilter colorFilter = new PorterDuffColorFilter(Color.RED, PorterDuff.Mode.LIGHTEN);
 
 // Adding a color filter to the whole view
 animationView.addColorFilter(colorFilter);