Describes Nancy Middleware as an OWIN MidFunc

 - Convert NancyMiddleware to a static MidFunc factory; the formalized owin spec for defining middleware
 - Adjust Nancy.Owin.AppBuilderExtensions accordingly
 - Using MS.Owin.Testing to test the IAppBuilderExtensions.

Due to MS.Buld.Bcl coming along with MS.Owin.Testing, willing to bet Tavis has a jip.