Bugfix close application properly

Fixed bug which triggered crashes of the application when it was incorporated into external applications

src/pygenplot/handlers/logger_widget.py

@@ -13,10 +13,6 @@ class LoggerWidget(QtWidgets.QPlainTextEdit,logging.Handler):
         super(LoggerWidget,self).__init__(parent)
         self.setReadOnly(True)
 
-    def close(self):
-        """Closes the handler."""
-        logging.Handler.close(self)
-
     def contextMenuEvent(self, event: QtCore.QEvent):
         """Opens a contextual menu.