Add Exception to CommandError for the better error message.

[dzmitryhil]

It was found in the responses from the testnet that the response contains an additional attribute with the detailed error.

The PR contains changes for the error message improvements.

You can try that code snippet (with updated code):

func main() {
	host := "wss://s.altnet.rippletest.net:51233/"
	remote, err := websockets.NewRemote(host)
	panicIfErr(err)
	amount, err := data.NewAmount("100000") // 0.1 XRP tokens
	tx := data.Payment{
		Amount: *amount,
		TxBase: data.TxBase{
			TransactionType: data.PAYMENT,
		},
	}
	// submit the transaction
	_, err = remote.Submit(&tx)
	fmt.Printf("%s\n", err)
}

func panicIfErr(err error) {
	if err != nil {
		panic(err)
	}
}

The output:

invalidTransaction 0  gFID: uncommon type out of range 0

Raw response.

{"error":"invalidTransaction","error_exception":"gFID: uncommon type out of range 0","id":1,"request":{"command":"submit","id":1,"tx_blob":"12000024000000006140000000000186A06880000000000000008114000000000000000000000000000000000000000083140000000000000000000000000000000000000000"},"status":"error","type":"response"}

---

The output if you run it from the master:

invalidTransaction 0