title: SpriteKit: add UIGestureRecognizer and detect which node was swiped
body: <p>In which method do I add a <code>UIGestureRecognizer</code> to my <code>SKScene</code>. And how do I detect which node was swiped? This doesn't seem to work:</p>
  
  <pre><code>-(id)initWithSize:(CGSize)size {    
      if (self = [super initWithSize:size]) {
  
      ...
  
      UISwipeGestureRecognizer *recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipe:)];
      recognizer.direction = UISwipeGestureRecognizerDirectionUp;
      [[self view] addGestureRecognizer:recognizer];
  
      }
      return self;
  }
  </code></pre>