Remove carSpeed in StreetEdge constructor.

- This reduce code clutter, and anyway settable parameters
do not belongs to constructor parameters.
- Also remove public no-arg StreetEdge constructor, not used.
Always use StreetEdge.getElevationProfileSegment()
Add StreetWithElevationEdge, extending StreetEdge.
Small code reformat.
Remove elevation from StreetEdge.

Make AreaEdge and PartialStreetEdge extending from StreetWithElevationEdge.
Update unit tests.

Note: this version will not work with elevation data.
Update comment on OSMPlainStreetEdgeFactory class.
Removed unused code in edge factory (OSM labels).
Remove OSM parameters to edge factories.
Renamed and moved edge factorie classes.

They can be (and will be) used in other context than OSM-only,
and do not depend on any OSM-related stuff anymore.
Add elevation flag in default edge factory.
Be more helpful in exception message for elevation.
Enable elevation flag in OTP configurator.
Use edge factory in shapefile graph builder.
Use StreetWithElevationEdge when needed.
Remove setElevationProfile() in StreetEdge.
Remove carSpeed parameter to edge factory.
Make isSlopeOverride() getter public.
Remove spurrious missing elevation data warnings.

When the edge has been flattened or slope override (stairs, etc...)
the printed warning is spurrious. Filter them out.
Merge pull request #1548 from laurentg/pse-optimizations

Remove elevationProfileSegment pointer from StreetEdge