title: SKEmitterNode particleAction not working iOS9 Beta
body: <p>I'm testing my app in iOS9 Beta 4 and finding lots of code that used to work in iOS8 that is no longer performing as expected. Another example is SpriteKit's SKEmitterNode "particleAction" property. The following code worked in iOS8 but does not work on iOS9:</p>
  
  <pre><code>// create the particle movement action
  SKAction *move = [SKAction moveByX:100 y:100 duration:5]; // also, I've tested several other SKActions, such as scaleBy, fade, rotate, to no effect here        
  
  // create a target node and add to the SKScene
  SKNode *targetNode = [SKNode node];
  targetNode.position = origin;
  [mySKSceneNode addChild:targetNode];
  
  // add an emitter node that has a target and an SKAction
  SKEmitterNode *flameTrail = [NSKeyedUnarchiver unarchiveObjectWithFile:[[NSBundle mainBundle]pathForResource:@"FlameAttack" ofType:@"sks"]];
  flameTrail.position = origin;
  flameTrail.particleAction = move; // TODO iOS9 compatibility issues!
  flameTrail.targetNode = targetNode;
  [mySKSceneNode addChild:flameTrail];
  </code></pre>
  
  <p>On iOS8 the code above would yield an SKEmitterNode that looked like sparks flying. On iOS9 the SKEmitterNode is totally invisible (does not appear in the SKScene at all). If I comment out the following line:</p>
  
  <pre><code>flameTrail.particleAction = move; // TODO iOS9 compatibility issues!
  </code></pre>
  
  <p>then I will see the SKEmitterNode in the scene but I will not see any motion associated with the particles.</p>
  
  <p>I've also tested this with several other SKActions and didn't see any change in results. I submitted a bug to Apple; in the meantime can anyone confirm/deny this problem or see a problem in the code?</p>