title: Swift 3.1 macos: Cant convert String to URL, Umlaute-Encoding
body: <p>I read a lot about converting and encoding now, tho im struggling to make things work:
  I want to convert a String containing Umlaute (such as ü,ä,ö) to URL, to execute removeItem(at: URL). Working perfectly fine without Umlaute.</p>
  
  <pre><code>pfadraus = "/Users/mdoe/Downloads/Test3 üKopie" 
  let uhk = "file://\(pfadraus.replacingOccurrences(of: " ", with: "%20"))"
  let uhk2 = URL(string: uhk)!
  </code></pre>
  
  <p>Always returns nil, I suspect some encoding should be done, tho I struggle to set that up as well. As said, in the end </p>
  
  <pre><code>let löschen = try FileManager.default.removeItem(at: uhk2)
  </code></pre>