GQueue API additions

[Soeren Sandmann <sandmann daimi au dk>]

Hi Tim

I have just committed the GQueue API additions in

http://bugzilla.gnome.org/show_bug.cgi?id=118439 

despite you moving the bug to the 2.6 API milestone. I did this
because:

  - The API has had several iterations

  - There is an extensive, complete test suite

  - Both the API and the g_list_nth() thing that you mention in the
    bug have been discussed on gtk-devel

  - The GRing bug has been WONTFIX'ed, and this was announced on
    gtk-devel without any comments.

  - The patch was effectively approved by Owen

Søren