Support .NET Platform Standard 1.6 (inc. .NET Core 1.0)

[khellang]

I figured it's time to start this discussion 😄

Here are some threads for reference:

castleproject/Core#90
nsubstitute/NSubstitute#192
devlooped/moq#168

There's a PR pending for .NET Core support in Castle.Core at castleproject/Core#92

[adamralph]

As soon as Castle.Core support the dotnet TFN I'm happy to do this.

[jeremymeng]

Would it be okay to start the work based on https://github.com/castleproject/Core/tree/netcore? Most of the big changes are already in. I am willing to give it a first stab.

[adamralph]

@jeremymeng I think would be fine to grab some custom binary to reference for now, so long as your are prepared to rebase/squash your commits back to something clean (or have someone else do that) when Castle for netcore (or whatever other name is goes by) is on NuGet.

[jchannon]

Where are we at with this?