Query Request Implementation

[kabudu]

Datacash query request implementation.

For reference: https://datacash.custhelp.com/app/answers/detail/a_id/1037/~/using-the-query-transaction

[pedanticantic]

Hi there, thank you for the pull request.

I'm so sorry it's taken so long to respond.

I think you're changes are basically okay - changing the syntax of the array initialisation is fine. However, I think there needs to be a little bit of documentation. Specifically:

It's not clear whether the request uses a datacash reference or a merchant reference, or if either will work. It sends "$this->getTransactionReference()" in the request, but it's not clear which of those references can be used. Could you add a comment before that line just to explain what values are accepted?

Could you document the new request in the "Basic Usage" section of the README.md file?

[pedanticantic]

I've just checked what "getTransactionReference()" returns, and it's the datacash_reference.

Therefore, could you document in the request class and in the README.md that it only passes the datacash_reference? Thanks!

Once you've done that, we'll merge it in and create a new release.