Additions and enhancements (#14)

- add interactive API repl
- enhance cluster status output (use -v)
- add more ccr commands
- refactoring

cmd/cluster.go

@@ -64,6 +64,12 @@ func ClusterStatus(conf *cfg.Config) *cli.Command {
 				Destination: &conf.All,
 				Aliases:     []string{"a"},
 			},
+			&cli.BoolFlag{
+				Name:        "verbose",
+				Usage:       "include verbose statistics",
+				Destination: &conf.Verbose,
+				Aliases:     []string{"v"},
+			},
 		},
 
 		Action: func(ctx context.Context, cmd *cli.Command) error {