title: URL nil after upgrade to swift 3.0
body: <p>URL is nil after covert to swift 3.0</p>
  
  <p>my swift2 code (This code works prefect)</p>
  
  <pre><code>let correctedAddress:String! = firstResult.stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.symbolCharacterSet())
  let url = NSURL(string: "https://maps.googleapis.com/maps/api/geocode/json?address=\(correctedAddress)")
  let task = NSURLSession.sharedSession().dataTaskWithURL(url!) { (data, response, error) -&gt; Void in
  </code></pre>
  
  <p>my swift 3 code after convert</p>
  
  <pre><code>print(firstResult)
  let correctedAddress:String! = firstResult.addingPercentEncoding(withAllowedCharacters: CharacterSet.symbols)
  print(correctedAddress)
  let url = URL(string: "https://maps.googleapis.com/maps/api/geocode/json?address=\(correctedAddress)")
  print(url)
  let task = URLSession.shared.dataTask(with: url!, completionHandler: { (data, response, error) -&gt; Void in
  </code></pre>
  
  <p>print</p>
  
  <pre><code>San Francisco, California, United States    
  %53%61%6E%20%46%72%61%6E%63%69%73%63%6F%2C%20%43%61%6C%69%66%6F%72%6E%69%61%2C%20%55%6E%69%74%65%64%20%53%74%61%74%65%73
  nil
  </code></pre>
  
  <hr>
  
  <p>Tried to look at the question in here. <a href="https://stackoverflow.com/questions/28514622/convert-string-to-nsurl-is-return-nil-in-swift">Convert String to NSURL is return nil in swift</a></p>
  
  <pre><code>var url : NSString = "https://maps.googleapis.com/maps/api/distancematrix/json?origins=\(self.latitud‌​e),\(self.longitude)&amp;destinations=\(self.stringForDistance)&amp;language=en-US" 
  var urlStr : NSString = url.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)! 
  var searchURL : NSURL = NSURL(string: urlStr)! 
  println(searchURL)
  </code></pre>
  
  <p>But, I still could figure out the NSUTF8StringEncoding since it occurs an error</p>