Gtk::PlacesSidebar: Add set_drop_targets_visible()
Gtk::PlacesSidebar: Add set_drop_targets_visible()

* gtk/src/placessidebar.hg: Add set_drop_targets_visible().
Update deprecation messages for set/get_show_connect_to_server().

GNOME/gtkmm,GNOME/gtkmm,GNOME/gtkmm,GNOME/gtkmm