No .net core version of the SDK

[brunzefb]

Hi,

I have played around with the .net core 2.0 preview SDK, and have a .net standard version of the BaseSpace SDK in my cloned repo. Also have TerminalVelocity as a .net Standard 2.0 dll -- in my fork of that project.

https://github.com/brunzefb/basespace-csharp-sdk -- feature/netcore2.0 branch
https://github.com/brunzefb/TerminalVelocity - feature/netcore2.0 branch

I tested it by writing code to ListProjects -- that part works -- I have not tested the rest.

Friedrich Brunzema.