Populates the main menu.

        The main menu looks as follows:
        Plugins
            - Plugin manager (fixed item)
            - Separator (fixed item)
            - <Plugin #1 name> (this is the parentMenu passed)
            ...
        If no items were populated by the plugin then there will be no
        <Plugin #N name> menu item shown.
        It is suggested to insert plugin configuration item here if so.

def populateMainMenu(self, parentMenu):
        """Populates the main menu.

        The main menu looks as follows:
        Plugins
            - Plugin manager (fixed item)
            - Separator (fixed item)
            - <Plugin #1 name> (this is the parentMenu passed)
            ...
        If no items were populated by the plugin then there will be no
        <Plugin #N name> menu item shown.
        It is suggested to insert plugin configuration item here if so.
        """
        parentMenu.addAction("Configure", self.configure)
        parentMenu.addAction("Collect garbage", self.__collectGarbage)