libqtlxqt - LXDE-Qt system integration plugin for Qt.

With this plugin, all Qt-based programs can adopt settings of
LXDE-Qt, such as the icon theme.

Unfortunately, Qt4 and Qt5 handle this totally differently,
so we need to have separated plugins for them.

The plugin for Qt5 is in the qt5 sub directory.
To use the plugin in Qt 5, we have to export the environment
variable QT_QPA_PLATFORMTHEME=lxqt. Then every Qt5 program
can load the theme plugin.
If, for some unknown reasons, the plugin is not loaded, we can
debug the plugin by exporting QT_DEBUG_PLUGINS=1.
Then, Qt5 will print detailed information and error messages
about all plugins in the console when running any Qt5 programs.

The plugin for Qt4 is in the qt4 directory.
In Qt 4, to let Qt load the plugin, export the environment variable
QT_PLATFORM_PLUGIN=lxqt or DESKTOP_SESSION=lxqt.
However, setting DESKTOP_SESSION might affect the behaviors
of other tools such as xdg-tools. If this is not the desired
effect, use QT_PLATFORM_PLUGIN.
