设置Qt依赖库路径

在Qt5.0版本以后，由于框架的改动，打包的程序安装到其它电脑会提示找不到Qt库的路径， 这时候需要注册这些库，如下：

void Util::registerPluginsDir(QDir &exeDir)
{
    QString pluginsRelPath = "qtplugins";
    QString platformsRelPath = "platforms";
    QString sqlDriversRelPath = "sqldrivers";
    QString imageformatsRelPath = "imageformats";

    QString pluginsPath = exeDir.absoluteFilePath(pluginsRelPath);

    QString platformsPath = QDir(pluginsPath).absoluteFilePath(platformsRelPath);
    QString sqlDriversPath = QDir(pluginsPath).absoluteFilePath(sqlDriversRelPath);
    QString imageformatsPath = QDir(pluginsPath).absoluteFilePath(imageformatsRelPath);

    QStringList pathes = QCoreApplication::libraryPaths();
    pathes << pluginsPath;
    pathes << platformsPath;
    pathes << sqlDriversPath;
    pathes << imageformatsPath;
    QCoreApplication::setLibraryPaths(pathes);
}