Kraken: remove journey_pattern_point_connection
Kraken: introduce notion of prev, next vehicle journey

This is used to represent how the vehicle journeys are linked
with each other.
This is used when several vj have the same block_id
Build_helper: handle prev/next vehicle_journey
Ed: link vehicle_journey of the same block_id together
Kraken: Use of prev/next vj

We don't use anymore the journey_pattern_connection to handle
block_id.

After computing a journey_pattern, if the used vj has a next_vj
we store it in a queue.

After computing all the journey_patterns, we look at all the vj
in this queue, and we try to apply them on the labels.
Kraken: new tests for stay_in
Kraken: try to fix stay_in_complexe UT
Raptor: add UT of a stay_in without any teleport
Builder: better handling of drop_off, pickup allowed
Kraken: fix building of raptor_path
Kraken: use of read_path in raptor_solutions
Kraken: fix apply_vj_extension

And small refactor of raptor_loop
Kraken: fix of UT
Ed: Update vj with prev and next vj
Ed: Fix deletion of vehicle_journeys
Kraken: add a not handle yet UT
Ed: Correction of a comment
Ed: sanity_check on build_block_id
Ed: remove debugging code, and set a log to trace
Ed: Improve definition of VehicleJourneys