add appveyor support for CI

[dvbarnes]

@ppande1020 or @mrobustelli I may need your help to set this up since I don't have the rights to see the repo with appveyor.

[ppande1020]

@dvbarnes Let me know! Never worked with appveyor so it will be fun to work on this.

[dvbarnes]

it's a build server, will also allow you to auto publish to nuget which should solve #7 as well

[ppande1020]

Sweet! That is cool! Let me know if you want to get on a call to discuss this or to discuss any of the other enhancements.

[ppande1020]

I was able to see test Helpers in appveyor from my account but the build failed.

[ppande1020]

So the build log tells me its not be able to recognize the dll's/nuget packages in the project. I recently changed all the references in all the projects in the solution to consume nuget packages for the kcura.relativity.client, relativity.api and everything else we would normally get from the SDK. I wonder if that is causing issues.

[mrobustelli]

I am denying the initial request for the appveyor because it wants "access to private data in relativitydev organization" I think this is a great idea, but want to see if we can get that limited to just the Test Helper project or get a more clear picture of what "private data" they are talking about. I know this is done all the time and there are probably some simple answers to these questions/problems. Will continue to work with everyone to get them figured out.