title: initWithContentsOfURL:error: returns (null) when the contents are special characters
body: <p><code>initWithContentsOfURL:error:</code> returns <code>(null)</code> when it should return <code>"São Tomé and Príncipe"</code>. I've tested it using text without special characters, and then it worked fine.</p>
  
  <pre><code>NSString *myURL = [NSString stringWithString:@"http://mywebsite.com/api-call.php"];
  NSURL *url = [[NSURL alloc] initWithString:myURL];
  NSString *strResult = [[NSString alloc] initWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];
  NSLog(@"%@",strResult);
  </code></pre>
  
  <p>I guess the problem is related with the encoding, but I don't know how to fix it.</p>