Nuke 1.0.0

• #30 Add new protocols and extensions to make it easy to add full featured image loading capabilities to custom UI components. Here's how it works:

extension MKAnnotationView: ImageDisplayingView, ImageLoadingView {
    // That's it, you get default implementation of all the methods in ImageLoadingView protocol
    public var nk_image: UIImage? {
        get { return self.image }
        set { self.image = newValue }
    }
}

• #30 Add UIImageView extension instead of custom UIImageView subclass
• Back to the Mac! All new protocol and extensions for UI components (#30) are also available on a Mac, including new NSImageView extension.
• #26 Add getImageTaskWithCompletion(_:) method to ImageManager
• Add essential documentation
• Add handy extensions to ImageResponse