title: SKSpriteNode does not let touches pass through when isUserInteractionEnabled false
body: <p>I'm attempting to create an overlay in SpriteKit which by using an <code>SKSpriteNode</code>. However, I want the touches to pass through the overlay, so I set <code>isUserInteractionEnabled</code> to false. However, when I do this, the <code>SKSpriteNode</code> still seems to absorb all the touches and does not allow the underlying nodes to do anything.</p>
  
  <p>Here's an example of what I'm talking about:</p>
  
  <pre><code>class 
  
  TouchableSprite: SKShapeNode {
      override func touchesBegan(_ touches: Set&lt;UITouch&gt;, with event: UIEvent?) {
          print("Touch began")
      }
  }
  
  class GameScene: SKScene {
      override func sceneDidLoad() {
          // Creat touchable
          let touchable = TouchableSprite(circleOfRadius: 100)
          touchable.zPosition = -1
          touchable.fillColor = SKColor.red
          touchable.isUserInteractionEnabled = true
          addChild(touchable)
  
  
          // Create overlay
          let overlayNode = SKSpriteNode(imageNamed: "Fade")
          overlayNode.zPosition = 1
          overlayNode.isUserInteractionEnabled = false
          addChild(overlayNode)
      }
  }
  </code></pre>
  
  <p>I've tried subclassing <code>SKSpriteNode</code> and manually delegating the touch events to the appropriate nodes, but that results in a lot of weird behavior.</p>
  
  <p>Any help would be much appreciated. Thanks!</p>