[Nautilus-list] bookmark window, TreeView

[jacob berkman <jacob ximian com>]

i started this patch but won't have a chance to work on it again for a
while, so i wanted to put it on bugzilla in case someone else wanted to
finish it.

it makes NautilusBookmarkList a subclass of GtkListStore for reasons
mentioned in:

http://bugzilla.gnome.org/show_bug.cgi?id=72723

jacob
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