Known problems fixed in GtkAda 2.22.0

- JC10-011 Gtkada.MDI gives focus when raising a window
  Problem:    When selecting a floating window via the /Window
              menu, there were a number of cases where the window was
              not properly raised (depending on your window manager and
              system). The MDI will now additionally give the text focus
              to that window.
  Workaround: Call Raise_Child manually to make sure the window was raised

- JC09-041 Gtk.Widget.Get_Snapshot fails and causes crashes
  Problem:    Calling Gtk.Widget.Get_Snapshot causes memory corruption and
              potentially crashes.
  Workaround: Fix the binding to Get_Snapshot: parameter Clip_Rect should be
              a Gdk.Rectangle.Gdk_Rectangle_Access rather than 
              a Gtk.Rectangle.Gdk_Rectangle.
