[gtkmm] User Data

[Leandro Fanzone <leandro hasar com>]

Thank you to all that helped me with the TreeView implementation, I have 
the coloured rows working. Now I need to use the get_user_data() call, 
and I see it has no mapping whatsoever in Gtk--. Is there a reason for 
this, something I must be aware of before using the gtk+ function?
Thank you again,

Leandro Fanzone.