title: NSSortDescriptor issue
body: <p>I am making a contact book App where I am fetching names from AddressBook and stored them in Core data and displayed the names on a table using <code>NSFetchedResultsController.However</code> the first index and section that comes up is # followed by the alphabets. But I want to do it like it is in native contact app i.e. # index should come at last.<br>
  I used the following <code>NSortDescriptor</code>:</p>
  
  <blockquote>
    <p>sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"fullName" ascending:YES ];</p>
  </blockquote>
  
  <p>here "fullName" is the <code>key</code> in core data which is made by concatenating first name and last name.
  And the section identifier is the first letter of "fullName" if the <code>fullName</code> doesn't start with alphabet, its section identifier is #.<br>
  I had searched about it and used <code>NSDiacriticInsensitiveSearch</code> in the <code>NSortDescriptor</code> comparator but it didn't worked. If any one has any idea then let me know.</p>
  
  <p>Here goes my code:</p>
  
  <pre><code>NSString *special = @"\uE000";
  if ([[self sectionName:contactName] isEqualToString:@"#"]) {                           
      sortName = [special stringByAppendingString:contactName];
  }
  else{
      sortName = contactName;
  }
  [newContact setValue:[self sectionIdentifier:sortName] forKey:@"sectionIdentifier"];
  [newContact setValue:sortName forKey:@"sortName"];
  </code></pre>
  
  <p>And here is the sort descriptor:</p>
  
  <pre><code>sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"sortName" ascending:YES];
  </code></pre>
  
  <p><code>[self sectionIdentifier:sortName]</code> this method returns # if sortName starts with a non alphabet and else it returns the alphabet by which it starts.</p>
  
  <p>newContact is the object of the entity.</p>