Improve Output of Search algorithms

[MoKob]

The current implementation of our search algorithms simply output a list of stops without considering lines / transfers.

To allow reasonable annotation, we should augment the output of the transit search algorithms. This output should probably consist of the following information:

• a list of stops and the line used to reach it - here we might need to distinguish between actual lines (from the data) and what is internally used as line. This could require a dedicated ID ?
• all transfers and their ID to allow correct annotation (type/...)

Possible further annotation requirements will be added to the ticket, as they arise.

[MoKob]

Intermediate stops (without according for different lines) landed in #59. We are missing their actual depart/arrival times, though.