def timeband_breadcrumb(action)
    referential_breadcrumb
    add_breadcrumb Chouette::Timeband.model_name.human(:count => 2), referential_timebands_path(@referential) unless action == :index
    add_breadcrumb breadcrumb_label(@timeband), referential_timeband_path(@referential, @timeband),:title => breadcrumb_tooltip(@timeband) if action == :edit