Initialize plugin: connect signals, setup actions, etc.

        It must be run at the end of __init__

def initialize_plugin(self):
        """
        Initialize plugin: connect signals, setup actions, etc.

        It must be run at the end of __init__
        """
        self.create_toggle_view_action()

        self.plugin_actions = self.get_plugin_actions() + [MENU_SEPARATOR,
                                                           self.undock_action]
        add_actions(self.options_menu, self.plugin_actions)
        self.options_button.setMenu(self.options_menu)
        self.options_menu.aboutToShow.connect(self.refresh_actions)

        self.sig_show_message.connect(self.show_message)
        self.sig_update_plugin_title.connect(self.update_plugin_title)
        self.sig_option_changed.connect(self.set_option)
        self.setWindowTitle(self.get_plugin_title())