title: PFQuery.getObjectWithId(objectId: String) --- 'AnyObject?' is not convertible to 'String' error --- Parse sdk 1.7.1 and Xcode 6.3
body: <p>I just updated Xcode to 6.3 and my parse sdk to 1.7.1. I knew from the apple docs that I was going to spend some time fixing some of my swift code on my iOS app. Xcode is happy with all my fixes except for one func that gets a parse class by id. I've dredged parse, apple, stackoverflow, and google for a fix, but I've been banging my head against this last fix for hours and desperately need some help from one of you super smart guys. I apologize in advance if this turns out to be a stupid question. I've been programming for a really long time, but I'm a noob to iOS.</p>
  
  <p>Below is a simple example of what I'm trying to do, which worked before I updated Xcode and parse sdk. Now Xcode gives me errors for each of the lines where I am trying to get the variables out from the PFObject. Errors for each line is like this: "'AnyObject?' is not convertible to 'String'" and "Cannot assign to immutable value of type 'String". Any insight would be greatly appreciated.</p>
  
  <pre><code>func getFakeObject(objectId: String) -&gt; FakeObject {
  
      var fakeObject: FakeObject = FakeObject()
      var query = PFQuery(className:"FakeObject")
      var loadedFakeObject = query.getObjectWithId(objectId)
      if loadedFakeObject != nil {
  
              fakeObject.objectId = objectId
              fakeObject.isActive = loadedFakeObject["isActive"] as! Bool
              fakeObject.desc = loadedFakeObject["desc"] as! String
              fakeObject.purchasePrice = loadedFakeObject["purchasePrice"] as! Double
              fakeObject.purchaseDate = loadedFakeObject["purchaseDate"] as! NSDate
              fakeObject.labels = loadedFakeObject["labels"] as [String]
  
      }
      return fakeObject
  }
  </code></pre>