RethinkDb.Test.Integration.GroupingTests fail under Microsoft .NET 4.5 on Windows

[mfenniak]

Apparently the GroupingTests fail in Windows w/ .NET; they throw exceptions at line 66 of TupleDatumConverterFactory.cs stating that the "object" type does not have a ConvertDatum method. I believe the cause of this is that anonymous types are considered internal, and therefore can't be recognized by the dynamic keyword in this context.

One fix would be to rewrite ReflectedConversion to use reflection, rather than dynamic. I think that might work.

Another fix would be to add non-generic IDatumConverter instances, and the use of dynamic in TupleDatumConverterFactory could be removed. However, this is a large change affecting a lot of code, particularly the complex DataContractDatumConverterFactory.

[mfenniak]

Confirmed fixed in Windows; all unit tests now pass in Windows.