title: Cannot parse json array as nsarray in swift 2
body: <p>I have the following json as a response :</p>
  
  <pre><code>[
  {
      "id_post": "1",
      "id_type": "1",
      "title": "I hffjj",
      "body": "nothing at all",
      "visitors": "0",
      "extrabutton": "none",
      "deviceid": "468af7f24ade50c9"
  },
  {
      "id_post": "2",
      "id_type": "1",
      "title": "suxk my ",
      "body": "sssusushshd",
      "visitors": "0",
      "extrabutton": "none",
      "deviceid": "468af7f24ade50c9"
  }
  ] 
  </code></pre>
  
  <p>I am trying to parse it as an <code>NSArray</code> as the following :</p>
  
  <pre><code>let task = session.dataTaskWithRequest(request) { data, response, error in
              guard data != nil else {
                  print("no data found: \(error)")
                  return
              }
  
              do {
                  if let jsonResult = try NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableContainers) as? NSArray {
                      print("Success: \(jsonResult)")
                  }
              } catch let parseError {
                  print(parseError)
              }
          }
  </code></pre>
  
  <p>I always get the error: </p>
  
  <pre><code>Error Domain=NSCocoaErrorDomain Code=3840 "JSON text did not start with array or object and option to allow fragments not set." UserInfo={NSDebugDescription=JSON text did not start with array or object and option to allow fragments not set.}
  </code></pre>
  
  <p>What am I doing wrong?</p>