<!--- Remove sections that do not apply -->

### 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.
{
    return CLIENT_VERSION_IS_RELEASE;
}
QString ClientModel::formatClientStartupTime() const
{
    return QDateTime::fromTime_t(nClientStartupTime).toString();
}
QString ClientModel::dataDir() const
{
    return QString::fromStdString(GetDataDir().string());
}
void ClientModel::updateBanlist()
{
    banTableModel->refresh();
}
static void ShowProgress(ClientModel *clientmodel, const std::string &title, int nProgress)
{
    
    QMetaObject::invokeMethod(clientmodel, "showProgress", Qt::QueuedConnection,
                              Q_ARG(QString, QString::fromStdString(title)),
                              Q_ARG(int, nProgress));
}
static void NotifyNumConnectionsChanged(ClientModel *clientmodel, int newNumConnections)
{
    
    QMetaObject::invokeMethod(clientmodel, "updateNumConnections", Qt::QueuedConnection,
                              Q_ARG(int, newNumConnections));
}
static void NotifyAlertChanged(ClientModel *clientmodel)