Make BoBRobotics::Viz::JoystickKeyboard more configurable

[neworderofjamie]

It would be nice if the mapping of SFML keys to axis, currently hard-coded here, could be configurable - probably via a YAML file. You could implement this in the constructor of JoystickKeyboard something like this:

// Read config values from file
{
    cv::FileStorage configFile(configFilename, cv::FileStorage::READ);
    if(configFile.isOpened()) {
        auto &configNode = configFile["config"];
        cv::read(configNode["leftStickVertical"], m_AxisKeys[HID::JAxis::LeftStickVertical], m_AxisKeys[HID::JAxis::LeftStickVertical]);
        // **TODO** other buttons and axes, ideally saving typing with loops!
    }
}

// Re-write config file
{
    cv::FileStorage configFile(configFilename, cv::FileStorage::WRITE)
    configFile << "config" << "{";
    configFile << "leftStickVertical" << m_AxisKeys[HID::JAxis::LeftStickVertical];
    // **TODO** other buttons and axes, ideally saving typing with loops!
    configFile << "}";
}