cmd/lncli: add sendtoroute command

This commit adds sendtoroute command to lncli. RPC command SendToRoute
is not yet implemented.

cmd/lncli/main.go

@@ -210,6 +210,7 @@ func main() {
 		pendingChannelsCommand,
 		sendPaymentCommand,
 		payInvoiceCommand,
+		sendToRouteCommand,
 		addInvoiceCommand,
 		lookupInvoiceCommand,
 		listInvoicesCommand,