Groups hierarchic view, User membership interfase in Admin/Users subtab

Attached patch implement subj.
I need comments on this because it uses tricky/ineffective code:

  1. I pass callback sub too display tree nodes.
  2. It’s slow enought since I didn’t find easy to get GroupMembers object
    from Groups object directly. So I fetch top level groups and fetch
    members for each this group and so on reqursively.

I any case this thing work for us and help me a lot manage our users.

			Best regards. Ruslan.

PS. patch against users tabs is required for normal tabs working.

hierarchic_groups_user_memberof_page.patch (7.84 KB)