getting error in xcode 6.1 final on Yosimite

@IBOutlet weak var iconView: UIImageView!
@IBOutlet weak var currentTimeLabel: UILabel!
@IBOutlet weak var temperatureLabel: UILabel!
@IBOutlet weak var humidityLabel: UILabel!
@IBOutlet weak var precipitationLabel: UILabel!
@IBOutlet weak var summaryLabel: UILabel!


    // privately stores the forecast.io api key
private let apiKey = "86d7a55107698f774f17ca8b0fad7ec6"

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    // My Personal Lat/long location: 43.034559, -89.389465
    // let forecastURL = "37.8267,-122.423"

        /* the baseURL stores the main, resusable portion of the url
        *  and inserts the private apiKey into the URL along with
        *  Along with the final portion in the forecastURL
        *  the lat/long would also be in its own variable in a real
        *  world application.
        */

    let baseURL = NSURL(string: "https://api.forecast.io/forecast/\(apiKey)/")
    let forecastURL = NSURL(string: "43.034559,-89.389465", relativeToURL: baseURL)


    let sharedSession = NSURLSession.sharedSession()
    let downloadTask: NSURLSessionDownloadTask = sharedSession.downloadTaskWithURL(forecastURL!, completionHandler: { (location: NSURL!, response: NSURLResponse!, error: NSError!) -> Void in

        if (error == nil) {
            let dataObject = NSData(contentsOfURL: location)
            let weatherDictionary:NSDictionary = NSJSONSerialization.JSONObjectWithData(dataObject!, options: nil, error: nil) as NSDictionary

            let currentWeather = Current(weatherDictionary: weatherDictionary)

            dispatch_async(dispatch_get_main_queue(), { () -> Void in
                self.temperatureLabel.text = "\(currentWeather.temperature)"
                self.iconView.image = currentWeather.icon!
                self.currentTimeLabel.text = "At \(currentWeather.currentTime!) it is"
                self.humidityLabel.text = "\(currentWeather.humidity)"
                self.precipitationLabel.text = "\(currentWeather.precipProbability)"
                self.summaryLabel.text = "\(currentWeather.summary)"
            })
        }

    })
    downloadTask.resume()

    //let weatherData = NSData(contentsOfURL: forecastURL!)
    //println(weatherData)
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

var currentTime: String?
var temperature: Int
var humidity: Double
var precipProbability: Double
var summary: String
var icon: UIImage?

init(weatherDictionary: NSDictionary) {
    let currentWeather = weatherDictionary["currently"] as NSDictionary

    temperature = currentWeather["temperature"] as Int
    humidity = currentWeather["humidity"] as Double
    precipProbability = currentWeather["precipProbability"] as Double
    summary = currentWeather["summary"] as String

    let currentTimeIntValue = currentWeather["time"] as Int
    currentTime = dateStringFromUnixtime(currentTimeIntValue)

    let iconString = currentWeather["icon"] as String
    icon = weatherIconFromString(iconString)
}

func dateStringFromUnixtime(unixTime: Int) -> String {
    let timeInSeconds = NSTimeInterval(unixTime)
    let weatherDate = NSDate(timeIntervalSince1970: timeInSeconds)

    let dateFormatter = NSDateFormatter()
    dateFormatter.timeStyle = .ShortStyle

    return dateFormatter.stringFromDate(weatherDate)
}

func weatherIconFromString(stringIcon: String) ->  UIImage {
    var imageName: String

    switch stringIcon {
        case "clear-day":
            imageName = "clear-day"
        case "clear-night":
            imageName = "clear-night"
        case "rain":
            imageName = "rain"
        case "snow":
            imageName = "snow"
        case "sleet":
            imageName = "sleet"
        case "wind":
            imageName = "wind"
        case "fog":
            imageName = "fog"
        case "cloudy":
            imageName = "cloudy"
        case "partly-cloudy-day":
            imageName = "partly-cloudy"
        case "partly-cloudy-night":
            imageName = "cloudy-night"
        default:
            imageName = "default"

    }

    var iconImage = UIImage(named: imageName)
    return iconImage!
}