gtk3: Fix some deprecations
Issue #544
GtkHBox
has been deprecated since 3.2. This was missed.
gtk_button_new_from_stock()
is deprecated in 3.10
Edited by Hubert Figuière
Issue #544
GtkHBox
has been deprecated since 3.2. This was missed.
gtk_button_new_from_stock()
is deprecated in 3.10