This adds the ability to mark ways with a user-defined
class in the profile. This class information will be included
in the response as property of the RouteStep object.
The new numbering uses the partition information
to sort border nodes first to compactify storages
that need access indexed by border node ID.
We also get an optimized cache performance for free
sincr we can also recursively sort the nodes by cell ID.
This implements issue #3779.
