Remove VS 2013 support and add VS 2017 support

[ThadHouse]

It looks like adding some things required for VS 2017 support is going to break VS 2013 support. I don't think this is a big issue, as we'll still be able to support VS 2015.

[ThadHouse]

I'm also going to be dropping 2015 support. I'm working on a unified deploy system that works with both the dotnet cli and vs, however that is going to require the new project system, which will only be supported by 2017 and later.

[rtrainer]

When will PR-42 be merged and released?