initialize mark time if set in config

Window.py

@@ -6,10 +6,15 @@ from datetime import *
 from AboutWindow import AboutWindow
 from Config import *
 
+DT_FORMAT = '%Y-%m-%d %H:%M:%S'
+
 class Window:
     def __init__(self, progName, ds, config):
         self.ds = ds
         self.config = config
+        self.mark = None
+        if self.config.get('mark') is not None:
+            self.mark = datetime.strptime(self.config.get('mark'), DT_FORMAT)
         self.shown_projects = []
         self.taskStart = datetime.now()
         self.monday = \