We can't filter on bounds when loading ways because we don't have the coordinates yet.

Since the nodes are loaded on the second pass, we'll just have to store all ways to start.
Can now output kilometers as the units in the description.
Can now handle unicode in names and ref.
Improved handling of two-coordinate ways.
Defaults for the filter now include all roads for reusability in surface output.

The curvature.py script has higher defaults.