title: UserDefaults.standard set nil Error in XCode 8 and Swift 3
body: <p>This seems a bug. I am trying to remove an existing value in the defaults.</p>
  
  <pre><code>UserDefaults.standard.set(nil, forKey: "test-me")
  let val = UserDefaults.standard.object(forKey: "test-me")
  print ("val=\(val)")
  </code></pre>
  
  <p>I got the following output -</p>
  
  <pre><code>val=Optional(&lt;62706c69 73743030 d4010203 04050608 09582476 65727369 6f6e5824 6f626a65 63747359 24617263 68697665 72542474 6f701200 0186a0a1 0755246e 756c6c5f 100f4e53 4b657965 64417263 68697665 72d10a0b 54726f6f 74800008 111a232d 3237393f 51545900 00000000 00010100 00000000 00000c00 00000000 00000000 00000000 00005b&gt;)
  </code></pre>
  
  <p>I am running in XCode 8 / iOS 10 / iPhone 7 simulator. </p>