Result: remove train_no_transfer accessor

    * Result: Add arrival_wings, departure_wings and is_wing accessors

      (a wing train is coupled to the respective departure, but has its own ID)

    * db-iris: Indicate wings in output

    * Result: Remove train_no_transfer accessor (was based on erroneous

      assumptions)

Travel::Status::DE::IRIS 0.08 - Thu Mar 12 2015

Travel::Status::DE::IRIS::Result->mk_ro_accessors(

	qw(arrival classes date datetime delay departure is_cancelled is_transfer

	  is_unscheduled is_wing line_no train_no_transfer old_train_id

	  is_unscheduled is_wing line_no old_train_id

	  old_train_no platform raw_id realtime_xml route_start route_end

	  sched_arrival sched_departure sched_platform sched_route_start

	  sched_route_end start stop_no time train_id train_no transfer type

sub set_ref {

	my ( $self, %attrib ) = @_;

	$self->{train_no_transfer} = $attrib{train_no};

	# TODO

	return $self;

Number of this train, unique per day. E.g. C<< 2225 >> for C<< IC 2225 >>.

=item $result->train_no_transfer

Number of this train after a following transfer, undefined if no such transfer

exists. See B<is_transfer> for a note about this.

Note that unlike B<old_train_no>, this information is always based on realtime

data (not included in any schedule) and only set for stations before the

transfer station, not the transfer station itself.

=item $result->type

Type of this train, e.g. C<< S >> for S-Bahn, C<< RE >> for Regional-Express,