UnboxISO8601DateFormatter.swift

// Extension making ISO8601DateFormatter usable as an UnboxFormatter
extension ISO8601DateFormatter: UnboxFormatter {
  public func format(unboxedValue: String) -> Date? {
    return self.date(from: unboxedValue)
  }
}

// Shim (extension not needed)
class ISO8601DateFormatter: DateFormatter {

    override init() {
        super.init()

        self.locale     = Locale(identifier: "en_US_POSIX")
        self.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"
        self.timeZone   = TimeZone(secondsFromGMT: 0)
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder:aDecoder)
    }
}