* Clean up unnecessary workarounds on the build project.
* Remove the need to specify the content root relative to the solution
and use a solution based on an assembly level attribute on the test
assembly created at build time.
* Remove non parameterless constructors.
* Add support for creating specialized factories from the base factory
and keep track of "child" factories for disposal.
* Add support for creating clients that handle cookies and redirects
automatically.
- aspnet/Testing#248
- xUnit no longer supports .NET 4.5.1
- update AppVeyor config so this framework version is available
- build tests for desktop .NET only on Windows