big doc commit, bug fix too

["Ross McFarland" <rwmcfa1 neces com>]

just made a doc commit that leaves doc_helper.pl with nothing left to document
once again. here's the changelog

        * xs/GdkWindow.xs: merged get_children and peek_children into one
        function that always uses peek children since we're copying the list
        anyway. also fixes decent bug where list was being freed from
        peek_children which would of likely caused big problems.

        * xs/GdkRegion.xs, xs/GdkWindow.xs, xs/GtkCellRenderer.xs,
        xs/GtkContainer.xs, xs/GtkTreeModel.xs, xs/GtkWidget.xs,
        xs/GtkWindow.xs: doc updates. some just made =for xxx, some fixed bad
        doc. just added new doc. complete according to doc_helper.pl at this
        point.

-rm