Add Google Play link on README
# Lottie for Android, [iOS](https://github.com/airbnb/lottie-ios), and [React Native](https://github.com/airbnb/lottie-react-native)
+<a href='https://play.google.com/store/apps/details?id=com.airbnb.lottie'><img alt='Get it on Google Play' src='https://play.google.com/intl/en_us/badges/images/generic/en_badge_web_generic.png' height="80px"/></a>
Lottie is a mobile library for Android and iOS that parses [Adobe After Effects](http://www.adobe.com/products/aftereffects.html) animations exported as json with [Bodymovin](https://github.com/bodymovin/bodymovin) and renders them natively on mobile!
