"Reduce Duplicates" option doesn't stay set

Here is a patch

Do you want to make a really review?

@@ -33,6 +33,8 @@ class views_handler_argument_string extends views_handler_argument {
       $options['require_value'] = array('default' => FALSE);
     }

+    views_many_to_one_helper::option_definition($options);

We are adding this to views_handler_argument_string, but I don't see views_many_to_one_helper::options_form called in that class.
Hence, when I add a string argument that has "many to one" (such as Taxonomy: Term), I don't actually see the "Reduce Duplicates" option.
So, that part needs work.

As for the views_handler_filter_many_to_one part, that seems okay. Will give it a test once the whole patch is complete.

I don't know why i did this, but obvious this is a error.

Here is a new version of the patch.

Makes sense.
Adding a feature to the argument handler can be done in a separate issue.

Committed to D6 and D7.