This change takes the existing typedefs for weight, duration and
distance, and makes them proper types, using the existing Alias
functionality.
Primarily this is to prevent bugs where the metrics are switched,
but it also adds additional documentation. For example, it now
makes it clear (despite the naming of variables) that most of the
trip algorithm is running on the duration metric.
I've not made any changes to the casts performed between metrics
and numeric types, they now just more explicit.
Changes the processing order in the edge based graph factory.
Instead of iterating over all outgoing edges in order, we compute the edge
expanded graph in the order of intersections.
This allows to remember intersection shapes and re-use them for all possible ingoing edges.
Also: use low accuracry mode for intersections degree 2 intersections
We can use lower accuracy here, since the `bearing`
after the turn is not as relevant for off-route detection.
Getting lost is near impossible here.
