- aspnet/Testing#248
- xUnit no longer supports .NET 4.5.1
- target .NET 4.6.1 in Microsoft.Owin.Security.Interop.Test; avoids .NET 4.5.2 System.Xml casing issue
- build tests for desktop .NET only on Windows
- except Microsoft.Owin.Security.Interop.Test; already skipped using repo.props
- enable binding redirects for one test project