Add support for .NET Standard

[cmeeren]

This is just what I need. Unfortunately, I need it for .NET Standard. Could you make it compatible with .NET Standard?

[wbish]

Check out v2.0.0.0 of the nuget package. That should help you out.

[danielcrenna]

As per my PR, this does not actually provide .NET Standard support, it provides .NET Standard libraries mixed with .NET 4.5 dependencies, making it require the full framework and not able to be used in pure .NET Core solutions (i.e. Linux & macOS).