[Tagging] route/forward/backward members in all types of routes

[Ilya Zverev]

Fernando Trebien wrote:
> 
> According to PTv2, this route needs to be broken into two, one per
> direction, and a route_master relation must be created for them.
> Without the forward/backward roles, I believe applications will not be
> able to easily find out the direction of travel of either since the
> route contains a single way, unless they parse the from and to tags,
> which are not required to match station names.

Exactly, you found one case when the role is useful. I use it in the 
Subway Processor/Validator for this.

Ilya