Add EvMenu support for ending on start node.

Currently, if the start node has options of None then any input causes a "Choose an option or try 'help'." message to display and then ending the menu. This supports ending the menu without eating input.

evennia/utils/evmenu.py

@@ -855,6 +855,8 @@ class EvMenu(object):
             self.helptext = _HELP_NO_OPTIONS if self.auto_quit else _HELP_NO_OPTIONS_NO_QUIT
 
         self.display_nodetext()
+        if not options:
+            self.close_menu()
 
     def close_menu(self):
         """