c# translation

Because of the suggestions below, here is the translation which should upgrade this kata to the newest version and remove restrictions of the older versions: https://www.codewars.com/kumite/6308dcade5ae64004ac017b6?sel=6308dcade5ae64004ac017b6

Really needs to be able to use a much newer compiler. That being said, I got major dopamine release when I solved it.

The buyItem tests are broken. The code related to checking the owner's balance fails (it seems web3.eth.getBalance(owner) is the culprit) and leads to the following error message:

Error: Invalid JSON RPC response: undefined
    at Object.InvalidResponse (node_modules/web3/lib/web3/errors.js:35:16)
    at HttpProvider.send (node_modules/web3/lib/web3/httpprovider.js:91:22)
    at RequestManager.send (node_modules/web3/lib/web3/requestmanager.js:58:32)
    at Eth.send [as getBalance] (node_modules/web3/lib/web3/method.js:145:58)
    at test/fixture.js:104:52
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)

I have commented it out to make the kata completable but either this test should be fixed (unless this is actually a problem with the platform which only the admins might be able to deal with), or the requirement about transfering the money should be removed.