Create a road and bridge network from OSM data

Creates a base graph object with the appropriate edge and vertex attributes from OSM.

konigsberg_graph(src, path_filter = automobile_highways,
  bridge_filter = all_bridges)

Arguments

src	An `osmar` or a `base_konigsberg_graph` object.
path_filter	A function that filters which Ways will be traversable in the graph. See `way_filters`.
bridge_filter	A function that marks which Ways are bridges that need to be crossed. See `bridge_filters`.

A konigsberg_graph object.