Update appveyor to use VS 2017
Update appveyor to use VS 2017

EDDiscovery/EDDiscovery,klightspeed/EDDiscovery,EDDiscovery/EDDiscovery,klightspeed/EDDiscovery,klightspeed/EDDiscovery,EDDiscovery/EDDiscovery,andreaspada/EDDiscovery,andreaspada/EDDiscovery