Fixes to GetMerchant

[ChrisG5]

Converted to VS2013

modified:   GoCardlessSdk/Api/MerchantResponse.cs

Fixed issued with next payout date and amount being null

modified:   GoCardlessSdk/GoCardlessSdk.csproj

Fixed missing nuget files

modified:   Sample.Mvc3/Sample.Mvc3.csproj

[ChrisG5]

Null values returned by GetMerchant in the NextPayoutDate and NextPayoutAmount fields cause library to throw a NullReferenceException. Have made these fields nullable to fix this issue.

[barisbalic]

Hi @ChrisG5 thanks very much for this it's actually a duplicate of #33. We have recently deprecated this library on NuGet. If we were to accept these changes or the ones from the aforementioned PR they would not make it into the NuGet library as it stands.

Do you have a strong preference on getting the fix merged in given this context?

[ChrisG5]

Hi Baris, apologies for the delay in responding. I think it would be worth getting the changes in GoCardlessSdk/Api/MerchantResponse.cs pulled in as it looks like I'm the third person to mention it on github so there must be others that have hit the same problem.

It's a shame the library is being deprecated. I think there is some good work here that really helps the .net community get up to speed much quicker with the GC api.