Use len(turn:lanes) for number of lanes in road classification

[daniel-j-h]

Our profiles parse the lanes=number tag but do not use turn:lanes to count number of lanes. If a way has turn:lanes but not lanes we do not set RoadClassification::num_lanes.

We should parse turn:lanes (and forward, backward, namespaced tags), count the | delimiters and set num_lanes accordingly.

Affects:

• coordinate extraction in roundabout handler
• traffic island detection and road width estimation in mergeable road detector
• bearing calculation in intersection generation