Expose RC parameter of Cardpay CompletePurchaseResponse

[rootpd]

Tatrabanka is able (upon request) return extra RC parameter for Cardpay responses, which describes the reason of Cardpay payment failure. At this point there's no way how to read it from CompletePurchaseResponse.

Could you please add it?

You can find the info about the parameter in section 4.3.1 of the documentation: https://www.tatrabanka.sk/cardpay/CardPay_technicka_prirucka_HMAC.pdf.

[tomaj]

Done in master right now (#15)

Do you have also file that documentation is referring to (response kody_CP.XLS)?

[rootpd]

Nope, that file doesn't seem to be openable :(