title: When i destroy my object in Swift it doesnt free my RAM memory
body: <p>This is a test, an action to create and one to destroy an object, but when I destroy it my RAM is still using same amount of memory(around <em>30mb</em>). </p>
  
  <pre><code>var missileImage: UIImageView!
  weak var img: UIImage!
  
  @IBAction func createImg(sender: AnyObject) {
      missileImage = UIImageView(frame: CGRectMake(CGFloat(arc4random() % 100), 200, 50, 30))
      img = UIImage(named: "house.jpg")
      missileImage.image = img
      missileImage.tag = 10001
      self.view.addSubview(missileImage)
  }
  
  @IBAction func destroyImg(sender: AnyObject) {
      self.view.viewWithTag(10001)?.removeFromSuperview()
      img = nil
      missileImage = nil
  }
  </code></pre>