[gtkada] ANNOUNCE: GtkAda 2.2.0 release

[Arnaud Charlet]

> Why was there so much change on the Gdk side of things?  The latest changes

There have been major API changes between Gtk+ 1.2 and Gtk+ 2.0 in order
to clean up some improper or incomplete APIs. GtkAda followed naturally these
changes.

There are clearly major changes between 1.2 and 2.x, for the better.
These major changes are sometimes needed in order to move forward and improve
things.

Note that there should be much less API breakage in future releases (e.g.
2.0 and 2.2 are almost 100% compatible).

Arno