When externalizing the modules, we started to 'require' for example ext-krb5, where we used to only 'suggest' it.
That's when AppVeyor started to fail, since those extensions are not available and have proven to be hard to install..
This workaround should do the trick until we stop including those externalized modules in releases.

* Create .appveyor.yml

* Fix tests for Windows platform

* Fix builtin webserver for Windows

* Properly kill process on Windows