Lottie-ios: Add delay option for animation.

[maurovc]

something common in iOS like:

animationView.play(delay: 0.5) { (finished) in
 // Finished code
}

[buba447]

Lottie has been completely rewritten in Swift as of 3.0 (https://github.com/airbnb/lottie-ios/pull/777)

I am closing all issues prior to this release to reduce the noise. If you continue to run into this issues or any issue with Lottie 3.0 please open a new ticket

For continued support of Lottie Objective-c please point to this branch: https://github.com/airbnb/lottie-ios/tree/lottie/objectiveC

[akashnimare]

@buba447 any way to add delay?