Document some GtkEntry functions as going away in GTK+ 3
Document some GtkEntry functions as going away in GTK+ 3

https://bugzilla.gnome.org/show_bug.cgi?id=646773

johne53/MB3Gtk-2,johne53/MB3Gtk-2,Distrotech/gtk,johne53/MB3Gtk-2,Unity-Technologies/gtk,Unity-Technologies/gtk,Unity-Technologies/gtk,Distrotech/gtk,Distrotech/gtk,Unity-Technologies/gtk,johne53/MB3Gtk-2,Distrotech/gtk,Distrotech/gtk,johne53/MB3Gtk-2,Unity-Technologies/gtk