Automate VSIX push to the VS marketplace

[alexdresko]

The AppVeyor build does create the VSIX. I just have to figure out how to create a deployment that optionally pushes it to the marketplace.

Need to version the package first. This looks helpful: https://github.com/madskristensen/ExtensionScripts/blob/master/AppVeyor/vsix.ps1

Also http://help.appveyor.com/discussions/questions/2640-publishing-vsix-to-my-get

Also https://www.visualstudio.com/en-us/docs/integrate/extensions/publish/command-line

[alexdresko]

Mads himself said this wasn't possible.

https://twitter.com/alexdresko/status/839616708100952069

Try again later.

[alexdresko]

Still not possible, BTW. Recent conversation with the VS team yielded no response, and Mads was included in the conversation.

I trust that Mads will make it happy eventually.