[gtkada] About new Gtk+ 2.2 and 2.4 APIs

[Arnaud Charlet]

Since there have been apparently some willingness to help completing
the GtkAda API recently, I'd like to point out that the Gtk+ 2.2 API
isn't completely covered yet by GtkAda 2.2, so that would be a good
starting point if people would like to contribute.

A pretty complete list of missing features for Gtk+ 2.2 can be found in
docs/2.2-missing.txt

Of particular interest would be all the functions taking a GdkDisplay/GdkScreen
parameter, to support multiple displays, since this is the most notable
addition between Gtk+ 2.0 and Gtk+ 2.2

Concerning Gtk+ 2.4, there are mainly new widgets such as the new
file selector, the new combobox, and the new menu API (GtkUIManager).

If you start working on those, do not hesitate to coordinate with us,
so that there are no duplicate effort between various contributors.

Arno