v5.5.3: - Changes from 5.5.2

@danpat danpat tagged this Jan 12, 2017 · 269 commits to master since this tag

    - Bugfixes:
      - PR #3504 - debug tiles were very slow to generate due to unnecessarily copying data in a hot loop.
      - PR #3556 - fix an assertion in the walking profile triggered by tight spiral stairwells
      - PR #3469 - don't assert when identical coordinates are supplied to some calculations - OSM data contains these, we shouldn't crash.
    - Enhancements:
      - backported 6ea9f9fdf19 - when anticipating upcoming lanes, consider how many lanes need to be crossed to get there.
      - when using osrm-datastore, it will attempt to clean up locks if it crashes.