Added flush method

Author: Chilipp

psyplot_gui/common.py

@@ -128,3 +128,6 @@ def __init__(self, logger, log_level=logging.INFO):
     def write(self, buf):
         for line in buf.rstrip().splitlines():
             self.logger.log(self.log_level, line.rstrip())
+
+    def flush(self):
+        pass