Segment grouping

[Agustin Alba Chicar]

After issue #138 is finished we need to create groups of lanes, inside segments that follow the topology stated in Maliput.

[Agustin Alba Chicar]

Code in issue #138 give us a std::vector<std::vector<DirectedWaypoint>> filled with valid and invalid waypoints. All the std::vector<DirectedWaypoint> have the same length which allows us to make a proper grouping. We need to change the code to allow this grouping and specify a base segment from which create all the lanes.

In addition we need to make the code compliant with the API, we need to:

• Add the segments the ability to hold more than one lane.
• Provide an index to the lanes in the correct order (increasing numbers, zero indexed, right-to-left ordering).
• Provide the do_left() and do_right() methods for lanes.

[Agustin Alba Chicar]

Already done the previous three points.