title: Value of type 'CGRect' has no member 'scaled'
body: <p>I'm trying to use <code>detectLandmarks</code> in swift4 but appear an error at <code>let faceBoundingBox = boundingBox.scaled(to: self.view.bounds.size)</code></p>
  
  <p>Anyone know how to fix it</p>
  
  <pre><code>func detectLandmarks(on image: CIImage) {
      try? faceLandmarksDetectionRequest.perform([faceLandmarks], on: image)
      if let landmarksResults = faceLandmarks.results as? [VNFaceObservation] {
          for observation in landmarksResults {
              DispatchQueue.main.async {
                  if let boundingBox = self.faceLandmarks.inputFaceObservations?.first?.boundingBox {
                      let faceBoundingBox = boundingBox.scaled(to: self.view.bounds.size)
  
                      //different types of landmarks
                      let faceContour = observation.landmarks?.faceContour
                      self.convertPointsForFace(faceContour, faceBoundingBox)    
                  }
              }
          }
      }
  }
  </code></pre>