     - returns: String length in number of characters.
     */
     public var length: Int {
-        return self.characters.count
+        return self.count
     }
 
     /** 

     - returns: i:th character in the string
     */
    subscript (i: Int) -> Character {
        return self[self.characters.index(self.startIndex, offsetBy: i)]
    }

    /**

    - returns: the substring from startIndex to the end of this string
    */
    public func substring(startIndex: Int) -> String {
        let start = self.index(self.startIndex, offsetBy: startIndex)
        return String(self[start..<self.endIndex])
    }

