urlEncode.swift

    private func urlEncodeString(_ string: String) -> String {
        #if swift(>=3.0)
            let allowedCharacterSet = (CharacterSet(charactersIn: "!*'();:@&=+$,/?%#[] ").inverted)
            if let escapedString = string.addingPercentEncoding(withAllowedCharacters: allowedCharacterSet) {
                return escapedString
            }
        #else
            let allowedCharacterSet = (NSCharacterSet(charactersInString: "!*'();:@&=+$,/?%#[] ").invertedSet)
            if let escapedString = string.stringByAddingPercentEncodingWithAllowedCharacters(allowedCharacterSet) {
                return escapedString
            }
        #endif
        Log.Error.log("Could not urlencode \(string)")
        return string
    }