Ported GladeWindow to GtkBuilder

Signed-off-by: Germán Poo-Caamaño <gpoo@gnome.org>
Ported FormatDialog to Gtk3

Regression: It is necessary to change the widget to choose
the output file

Signed-off-by: Germán Poo-Caamaño <gpoo@gnome.org>
Port Sort dialog to Gtk3

Signed-off-by: Germán Poo-Caamaño <gpoo@gnome.org>