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### Issue description
The datadir field on the debug window displays incorrectly if the profile folder name is accented.

### How to reproduce
1. Create a profile with accented profile folder name (àèìòùáéíóú)
2. Run bitcoin core with the default datadir
3. Go to the debug window and look at the datadir field

### Expected behaviour
The datadir folder path should display correctly.

### Actual behaviour
Accented characters display as a unknown character question mark.

### Screenshots
![Debug Window](https://cloud.githubusercontent.com/assets/11365204/20029647/41dee90e-a352-11e6-8784-e5a48798d62e.png)


### Confirmed affected versions
The bug has been tested on the following implementations:

- v0.13.1 from source cross-compiled for Windows x64 on a Ubuntu 14.04 enviroment
- 0.13.0 official Windows x64 binary

### Additional debug info
Copying and pasting the text into a program that is known to support accented characters (Such as Notepad++) still displays unknown character symbols.
{
    Q_UNUSED(reply);
    QString errString;
    Q_FOREACH (const QSslError& err, errs) {
        qWarning() << "PaymentServer::reportSslErrors: " << err;
        errString += err.errorString() + "\n";
    }
    Q_EMIT message(tr("Network request error"), errString, CClientUIInterface::MSG_ERROR);
}
void PaymentServer::setOptionsModel(OptionsModel *_optionsModel)
{
    this->optionsModel = _optionsModel;
}
void PaymentServer::handlePaymentACK(const QString& paymentACKMsg)