message: fix(animations): add onDestroy method to NativeScriptAnimationPlayer
  Needed in order to implement correctly the AnimationPlayer interface.
  Introduced by:
diff: @@ -87,6 +87,7 @@ export class NativeScriptAnimationPlayer implements AnimationPlayer {
  onStart(fn: Function): void { this._startSubscriptions.push(fn); }
  onDone(fn: Function): void { this._doneSubscriptions.push(fn); }
  + onDestroy(fn: Function): void { this._doneSubscriptions.push(fn); }
  private _onStart() {
  if (!this._started) {
  