router: update interface (#1732)

* router: replace Start and Stop with Close

* router: update default network to micro

* router: update tests

router/router.go

@@ -11,7 +11,7 @@ var (
 	// DefaultName is default router service name
 	DefaultName = "go.micro.router"
 	// DefaultNetwork is default micro network
-	DefaultNetwork = "go.micro"
+	DefaultNetwork = "micro"
 	// DefaultRouter is default network router
 	DefaultRouter = NewRouter()
 )
@@ -32,10 +32,8 @@ type Router interface {
 	Lookup(...QueryOption) ([]Route, error)
 	// Watch returns a watcher which tracks updates to the routing table
 	Watch(opts ...WatchOption) (Watcher, error)
-	// Start starts the router
-	Start() error
-	// Stop stops the router
-	Stop() error
+	// Close the router
+	Close() error
 	// Returns the router implementation
 	String() string
 }