Callback to prompt the user whether to quit Guake or not.

def accel_quit(self, *args):
        """Callback to prompt the user whether to quit Guake or not.
        """
        procs = self.notebook_manager.get_running_fg_processes_count()
        tabs = self.notebook_manager.get_n_pages()
        notebooks = self.notebook_manager.get_n_notebooks()
        prompt_cfg = self.settings.general.get_boolean('prompt-on-quit')
        prompt_tab_cfg = self.settings.general.get_int('prompt-on-close-tab')
        # "Prompt on tab close" config overrides "prompt on quit" config
        if prompt_cfg or (prompt_tab_cfg == 1 and procs > 0) or (prompt_tab_cfg == 2):
            log.debug("Remaining procs=%r", procs)
            if PromptQuitDialog(self.window, procs, tabs, notebooks).quit():
                log.info("Quitting Guake")
                Gtk.main_quit()
        else:
            log.info("Quitting Guake")
            Gtk.main_quit()