cmd/lncli: implement remaining RPC commands

Currently positional arguments *are not* supported, and all arguments
must be passed via unix-style command line arguments.

In a later commit support for concurrent positional, and manually
specified arguments will be added.

cmd/lncli/main.go

@@ -51,6 +51,10 @@ func main() {
 		NewAddressCommand,
 		SendManyCommand,
 		ConnectCommand,
+		OpenChannelCommand,
+		CloseChannelCommand,
+		ListPeersCommand,
+		WalletBalanceCommand,
 		ShellCommand,
 	}