Move the link to Hasher.cs from Misc to Core\Misc so Visual Studio doesn't create an empty Misc directory every time you build.
CSHARP-875: Remove NotImplementedExceptions from legacy API, either by implementing or removing the method.
CSHARP-1074: Reimplement MongoCollection Count using Core operation.
CSHARP-1074: Reimplement MongoCollection Group using operation in Core.