Face rect detection

[KimDarren]

To get the detected faces result.

let image = UIImage(named: "image_contains_faces")
image.face.detect { result in
  switch result {
  case .success(let rects):
    // rects: [CGRect]
  case .notFound:
    // no faces founded.
  case .failure(let error): 
    // any error occurred.
  }
}