title: Convert String to CLLocationCoordinate2D in swift
body: <p>using Firebase as my backend, I've got a series of strings that are latitude and longitude coordinates, how can I convert them to CLLocationCoordinate2D so that I can use them for annotations? 
  Here is the code that gets the info from Firebase every time its updated    </p>
  
  <pre><code>var UpdateRef = Firebase(url:"https://ici.firebaseio.com/users")
  
  UpdateRef.observeEventType(.ChildChanged, withBlock: { (snapshot) in
      let MomentaryLatitude = snapshot.value["latitude"] as? String
      let MomentaryLongitude = snapshot.value["longitude"] as? String
      let ID = snapshot.value["ID"] as? String
  
      println("\(MomentaryLatitude)")
  
      var Coordinates = CLLocationCoordinate2D(latitude: MomentaryLatitude as
          CLLocationDegrees, longitude: MomentaryLongitude as CLLocationDegrees)
  
  }
  </code></pre>
  
  <p>The last line doesn't work, what should I use instead?</p>