Enable filtering on (common) street segments

[botanize]

This is simply the ability to select common routing across multiple routes and limit the analyses and visualizations to those common segments.

Once this work you can accurately compare travel times and speeds across routes.

Tools should allow selection of locations along route shapes to use as endpoints. All positions along route and between endpoints would be included within the analysis.

• Use a single shape as a template for selecting endpoints
• Match the endpoints from template shape to all other shapes (this works in both directions of travel if shapes share centerlines at endpoints)
• Group shapes by direction of travel on segment
• Calculate shape_dist_traveled offsets to align shapes, by direction. Calculate shape_dist_traveled if not included in GTFS shapes.
• filter vehiclePositions to just points with avl_dist_traveled on shape between offsets by shape.