Error calling smart contract functions with parameters

Hi!

Thanks for your awesome work, your library is great and has saved me lots of time and headaches.

I am using it with an ESP32 WROOM and I've been able to: 1) Send transaction to address 2) Call smart contract functions 3) Send transactions to smart contract functions **without parameters**.

However, I get an error every time I try to send a transaction to a smart contract function that contains some arguments. Here is an example:

## Working
### C++ code
```
string param = contract.SetupContractData("modifyNumber()");
string result = contract.SendTransaction(nonceVal, gasPriceVal, gasLimitVal, &contractAddrStr, &callValue, ¶m);
```

### Solidity code

```
contract Test {

uint8 public number = 20;

function modifyNumber() public {
number = 100;
}

}
```

## Not working
### C++ code
```
uint8_t newNum = 100;
string param = contract.SetupContractData("modifyNumber(uint8)", &newNum);
string result = contract.SendTransaction(nonceVal, gasPriceVal, gasLimitVal, &contractAddrStr, &callValue, ¶m);
```

### Solidity code

```
contract Test {

uint8 public number = 20;

function modifyNumber(uint8 newNum) public {
number = newNum;
}

}
```

## Error
The error occurs in `contract.SetupContractData(...)`, whenever the provided function contains some parameters.
The output error is of type:
`Guru Meditation Error: Core 1 panic'ed (LoadProhibited). Exception was unhandled`

Thank you in advance!