InaSAFE issue #463

    def unload(self):
        """Gui breakdown procedure (for QGIS plugin api).

        This method is called by QGIS and should be used to *remove*
        any graphical user interface elements that should appear in QGIS.

        Args:
           None.
        Returns:
           None.
        Raises:
           no exceptions explicitly raised.
        """
        # Remove the plugin menu item and icon
        self.iface.removePluginMenu(self.tr('InaSAFE'),
                                    self.actionDock)
        self.iface.removeToolBarIcon(self.actionDock)
        self.iface.removePluginMenu(self.tr('InaSAFE'),
                                    self.actionKeywordsDialog)
        self.iface.removeToolBarIcon(self.actionKeywordsDialog)
        self.iface.removePluginMenu(self.tr('InaSAFE'),
                                    self.actionResetDock)
        self.iface.removeToolBarIcon(self.actionResetDock)
        self.iface.removePluginMenu(self.tr('InaSAFE'),
                                    self.actionOptions)
        self.iface.removeToolBarIcon(self.actionOptions)
        self.iface.removePluginMenu(self.tr('InaSAFE'),
                                    self.actionImpactFunctionsDoc)
        self.iface.removeToolBarIcon(self.actionImpactFunctionsDoc)
        self.iface.mainWindow().removeDockWidget(self.dockWidget)
        self.dockWidget.setVisible(False)
        self.dockWidget.destroy()
        QObject.disconnect(self.iface,
            SIGNAL("currentLayerChanged(QgsMapLayer*)"),
            self.layerChanged)

        # Try to force unloading of all modules see issue #463
        # https://github.com/AIFDR/inasafe/issues/463

        for myKey in sys.modules.keys():
            if 'safe' in myKey:
                try:
                    del sys.modules[myKey]
                except:
                    pass

        try:
            myLogger = logging.getLogger('InaSAFE')
            myLogger.handlers = []
        except:
            pass