Merge branch 'cli-error-empty-new-group' of dan/cwtch into master

app/cli/main.go

@@ -309,7 +309,7 @@ func main() {
 				fmt.Printf("Error inviting peer to group, usage: %s\n", usages["invite-to-group"])
 			}
 		case "new-group":
-			if len(commands) == 2 {
+			if len(commands) == 2 && commands[1] != "" {
 				fmt.Printf("Setting up a new group on server:%v\n", commands[1])
 				id, _, err := app.Peer.StartGroup(commands[1])
 				if err == nil {