WIP: Add binding for /Gtk/DialogsUseHeader in appearance dialog
Partial solution for #235. Adds a checkbox to the
Settings tab of
xfce4-appearance-settings with a binding to
Personally, I have been setting
/Gtk/DialogsUseHeader manually (to false) because I generally prefer my buttons at the bottom of dialogs. So having this be selectable in a user-friendly way would be a welcome change.