Set up AppVeyor to publish releases to Github's release functionality

[mattlorimor]

Probably want to make AppVeyor only build on tag pushes and prevent AppVeyor from doing version number business.

[mynkow]

@mattlorimor I can do this easily. Just ping me here that this is still on the roadmap

[mattlorimor]

@mynkow - This is definitely still on the roadmap. It's not a huge deal to have to go in and hit "build" in AppVeyor, but it'd be way more convenient to just have to throw a tag up.

[mynkow]

@mattlorimor did you come up with a name for the nuget package?

[mynkow]

Ohh, I misread this issue. I am doing a PR which is doing slightly different thing. You could check it #19