WTS1 app does not launch if .NET core not installed

[MangyCoyote]

If you download *zip 1.0 release, uncompress files to folder and run it, app does not do anything.
Suspicion is, app has been run on a host without .NET core installed.

If that is true, we should verify .NET core is installed (if it's even possible) before execution.
Mark .NET core into documentation requirements.

Related to documentation: user should be notified he suppose to unzip all files in *zip file and how to run an app.