Add Transactions to netstandard ref

[weshaggard]

Fixes #157.

cc @terrajobst @saurabh500 @divega

@marek-safar @akoeplinger can you guys confirm that you have these already in xamarin and they just aren't in our reference platform or will they require work for you guys to add?

[akoeplinger]

From a quick look most if not all seems to be there on Xamarin, we'd just need to generate the reference .cs for System.Transactions.dll. I'll see if I can do that tomorrow.

[weshaggard]

Thanks @akoeplinger

[jimcarley]

Some things I can imagine NOT being in the Xamarin implementation are

Transaction.EnlistPromotableSinglePhase(IPromotableSinglePhaseNotification promotableSinglePhaseNotification, Guid promoterType)

Transaction.PromoterType
Transaction.GetPromotedToken
Transaction.SetDistributedTransactionIdentifier
TransactionInterop.PromoterTypeDTC

These were added to .NET on 2015-08-07 to support SQL Azure's ability to do distributed transactions between SQL Azure instances without using MSDTC. The reference snapshot for Xamarin may have been take before that.

[akoeplinger]

@jimcarley correct, I added stubs that throw NotImplementedException for those to Mono yesterday.

[terrajobst]

@jimcarley @akoeplinger can we implement them in principle? I assume the impl we use is part of reference source.

[akoeplinger]

@terrajobst they seem to be implemented in corefx already. We'll most likely just replace our implementation with that one.

[jimcarley]

Yes, they should be able to be implemented in Mono/Xamarin. They are implemented in corefx.

[terrajobst]

Sounds good. So this wouldn't be a permanent stub.