Created utilities for converting to/from networkx. Renamed tests to be valid python modules (changed '-' to '_').
Adding some helpers to get the sample files.
Minor
Making routing with rounded corners faster (no longer creating so many temporary Point objects).
Fixed issue introduced on routing which was silently failing.
Added missing header.
Merge pull request #6 from fabioz/master

Added some utilities to interact with networkx, renamed test files so that they're valid python names