pass this to setup. Fixes #536

Author: graingert

lib/Server.js

@@ -254,8 +254,8 @@ function Server(compiler, options) {
 
 		setup: function() {
 			if(typeof options.setup === "function")
-				options.setup(app);
-		}
+				options.setup(app, this);
+		}.bind(this)
 	};
 
 	var defaultFeatures = ["setup", "headers", "middleware"];