Oneway roads need to be taken into account when loading OSM data

[d3netxer]

The 'oneway' tag doesn't seem to be retained during the load_osm modules initialReadIn method (https://github.com/worldbank/GOSTnets/blob/master/GOSTnets/load_osm.py#L328). The add_missing_reflected_edges function in GOSTnets core can actually take oneway tags into account. Need to look into further...