[GraphHopper] Elevation data & two weights per edge

[Peter K]

Hi there,

please check out and try a new feature:
https://github.com/graphhopper/graphhopper/pull/169

Many thanks goes to @NopMap!

I would like to know your ideas/questions/experience before merging this
into master!

In order to implement this it was necessary to introduce a 'reverse'
flag in the Weighting.calcWeight method. With other changes (like
several to CH) it is possible to store two weights per edge in
GraphHopper. This could be useful for a traffic jam scenario as well:
one direction is slow while the other is faster etc. Storing this
information in one edge makes it easier to handle and it is more compact.

Regards,
Peter.