XSegEditor: added view lock at the center by holding shift.

main.py

@@ -22,6 +22,8 @@ if __name__ == "__main__":
         def __call__(self, parser, namespace, values, option_string=None):
             setattr(namespace, self.dest, os.path.abspath(os.path.expanduser(values)))
 
+    exit_code = 0
+    
     parser = argparse.ArgumentParser()
     subparsers = parser.add_subparsers()
 
@@ -262,7 +264,9 @@ if __name__ == "__main__":
     def process_xsegeditor(arguments):
         osex.set_process_lowest_prio()
         from XSegEditor import XSegEditor
-        XSegEditor.start (Path(arguments.input_dir))
+        global exit_code
+        exit_code = XSegEditor.start (Path(arguments.input_dir))
+        
     p.add_argument('--input-dir', required=True, action=fixPathAction, dest="input_dir")
 
     p.set_defaults (func=process_xsegeditor)
@@ -313,7 +317,10 @@ if __name__ == "__main__":
     arguments = parser.parse_args()
     arguments.func(arguments)
 
-    print ("Done.")
+    if exit_code == 0:
+        print ("Done.")
+        
+    exit(exit_code)
     
 '''
 import code