To automate creation, NuGet packages should be created by AppVeyor

[craigfowler]

As a part of my CI build process, I would like to have AppVeyor automatically create NuGet packages for the solution. These should then be packaged as build artifacts, for later download and inspection.

Additionally, if the current AppVeyor build is a tagged commit which matches the semantic version pattern, then I would like those packages to be pushed to my NuGet feed.

There is some documentation about publishing packages although I think I might just do it from the command line build script.

[craigfowler]

It appears that these two environment variables will be useful:

• APPVEYOR_REPO_TAG - true if build has started by pushed tag; otherwise false
• APPVEYOR_REPO_TAG_NAME - contains tag name for builds started by tag; otherwise this variable is undefined