I'm having this issue as well, in both VS 2015 PRO, and VS 2017 PRO.
In attempting to self resolve, I've uninstalled the SDK from both 2015 and 2017. Downloaded from the web, and downloaded from the marketplace from within Visual Studio.
Just saw a response on the GitHub issue from Matt Masson:
We're working on resolving the issue (problem with our build system) - hoping to have a fix out tomorrow night.
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