读写默认配置文件：

UserDefault::getInstance()->setStringForKey("data","Hello lidaha!");

    CCLOG("%s",UserDefault::getInstance()->getStringForKey("data.ini","Hello World"));

读写文件：

auto fu = FileUtils::getInstance();

    CCLOG("%s",fu->getWritablePath());  //获取允许操作的目录

    //打开文件
    FILE *fp = fopen(fu->fullPathFromRelativeFile("data.txt",fu->getWritablePath()).c_str(),"w");

    fprintf(fp,"Hello Lidaha!\n");

    fclose(fp);
    //读取文件数据
    auto dt = fu->getDataFromFile(fu->fullPathFromRelativeFile("data.txt",fu->getWritablePath()));

    CCLOG("%s",dt.getBytes());