fix(animations): add onDestroy method to NativeScriptAnimationPlayer

Needed in order to implement correctly the AnimationPlayer interface.
Introduced by: angular/angular@4577b7c

Author: sis0k0

nativescript-angular/animation-player.ts

@@ -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) {