title: xcode 7 generates core data entity with additional CoreDataProperties category
body: <p>I have strange new feature in xcode 7, when I generate new NSManagedObject subclass then xcode create two classes: entity and their CoreDataProperties category, which contain full implementation. In picture below an example what I mean.</p>
  
  <p><a href="https://i.stack.imgur.com/KLTiR.png"><img src="https://i.stack.imgur.com/KLTiR.png" alt="enter image description here"></a></p>
  
  <p>I cannot find any documented info about this, who can explain why it works so</p>