bpo-5680: IDLE: Customize running a module (GH-13763)

The initialize options are 1) add command line options, which are appended to sys.argv as if passed on a real command line, and 2) skip the shell restart. The customization dialog is accessed by a new entry on the Run menu.

Lib/idlelib/mainmenu.py

@@ -76,6 +76,7 @@ menudefs = [
    ('Python Shell', '<<open-python-shell>>'),
    ('C_heck Module', '<<check-module>>'),
    ('R_un Module', '<<run-module>>'),
+   ('Run... _Customized', '<<run-custom>>'),
    ]),
 
  ('shell', [