Merge pull request #22 from manbeardgames/develop

Null check for invoking OnAnimationEnd. Related Issue #21

Author: manbeardgames

source/MonoGame.Aseprite/Graphics/AnimatedSprite.cs

@@ -547,7 +547,7 @@ public void Stop()
             if (Animating)
             {
                 Animating = false;
-                OnAnimationEnd.Invoke();
+                OnAnimationEnd?.Invoke();
             }
         }