Improve ShapeBuilder

[xivk]

Improve shape builder by:

• Resolving not only the closest point.
• Find the best route 'along' a stop, not just to and from.

An example of blind resolving and routing between stops:

http://geojson.io/#id=gist:anonymous/e5d32e97bd395824f66365d741bdc87d&map=17/51.25620/4.80518