title: dealloc in Swift
body: <p>I would like to perform some cleanup at the end of a view controller's life, namely to remove an <code>NSNotificationCenter</code> notification. Implementing <code>dealloc</code> results in a Swift compiler error:</p>
  
  <pre><code>Cannot override 'dealloc' which has been marked unavailable
  </code></pre>
  
  <p>What is the preferred way to perform some cleanup at the end of an object's life in Swift?</p>