* Remove 3.0.101 and update SDK to 3.1.101
* Update projects to TargetFramework=netcoreapp3.1
* Update scripts, azure-pipelines.ps1 and README to netcoreapp3.1, remove netcoreapp3.0 support
* Set up CI with Azure Pipelines
* Add global.json
* Update projects to latest Windows SDK and v142 compiler
* Update README
* Remove .NET Framework Projects, and remove .netcore from project names