Refactor the OSRM/BirdDistance management

[greenscientist]

This:

• Split The OsrmFetcher into 2 classes and a base class. The OSRM side and Bird distance (now Euclidean) are in their own class. We pass the desired object to the Calculator constructor.
• Add a CLI option so active the Euclidean (Bird distance) mode
• Add a check for errors from OSRM. (Like if the server is not running)