CTree inheritance from CList

[Elliot Lee <sopwith redhat com>]

gtk_widget_show() works on all GtkWidgets, so gtk_clist_set_row_data()
should work on CTree's too. However, gtk_clist_set_row_data() and
gtk_ctree_set_row_data() have different (and possibly incompatible)
signatures.

This happens to work OK for C programs most of the time, but sucks in
languages such as Objective C, where all methods with the same name (in
this specific example, "set_row_data") must have the same signature.

The CTree analogues for the CList routines also breaks expected behaviour.
For example, gtk_ctree_set_row_data() just sets the data directly, without
sending the select_row signal that gtk_clist_set_row_data() does.

Perhaps:

(a) If gtk_clist_set_row_data() doesn't work for subclasses, perhaps it
    needs to be genericized so it will
	or
(b) GtkCTree doesn't really have that much in common with GtkCList
	or
(c) gtk_ctree_set_row_data() needs to be renamed, and also somehow
    implemented in terms of gtk_clist_set_row_data()

FOCUS on object-orientation :)
-- Elliot
Do you ever just feel thankful that you know me and have access to my
dementia? Explain. Be prepared to discuss in class.