Port to .NET Standard 2.0

[ggeurts]

Rhino code and tests have been ported to .NET Standard 2. Projects have been ported to the common project system and dependencies on external libraries replaced with NuGet references. Tests have been updated to use xUnit 2.0. Tests also use SQL Server LocalDB instead of SQL Server Express.

The following features are not available for the .NET Standard 2 platform:

• SQL Server batch operations, because SqlCommandSet is not (yet) available on the .NET Core platform;
• Boo DSL support, because no Boo port is available for .NET Core.

A new Rhino.Etl.Infrastructure.ConnectionProvider API has been added to provide a way to define and open connections that does not rely on XML configuration files.

[ggeurts]

A working System.Data.SqlClient.SqlCommandSet implementation should be available when .NET Core 3 is released (see https://github.com/dotnet/corefx/issues/29391).

[ggeurts]

System.Data.SqlClient 4.7.0 preview now has a working SqlCommandSet implementation, which means that except for the DSL logic all functionality is available for .NET Core.

[sundarbabu-dev]

Is this .Net core support to be released sometime this year? WE are having 40+ ETL packages that are using rhino ETl & Rhino ServiceBus. I would like to try .Net Core update to try to improve performance and multi platform capability.

[yvsean]

I'm not sure it would necessarily be the best to merge this into the main branch, for backwards compatibility purposes, but I think this fork looks great. Is there any chance of getting it up on NuGet independantly?