[Routing] Ferry routing

[Dennis Luxen]

> depends on each service, this one is typically  1-3 days behind. I think
> they want 1 day but with all the recent changes with the redaction it
> has been a bit more in the last days
> http://map.project-osrm.org

It is updated daily with a lag of roughly 8 hours. Changes as fresh as
7pm CET will show up the next day. Each update is automatically
announced on twitter at https://twitter.com/ProjectOSRM

Route=ferry tags are taken into account, but it is not possible to start
or end a route on water. Start and end markers have to be on dry land.

--Dennis