Turn Angles in OSRM were computed using a lookahead of 10 meters.

This PR adds more advanced coordinate extraction, analysing the road
to detect offsets due to OSM way modelling.

In addition it improves the handling of bearings. Right now OSM reports
bearings simply based on the very first coordinate along a way.
With this PR, we store the bearings for a turn correctly, making the
bearings for turns correct.

features/guidance/turn.feature

@@ -827,16 +827,16 @@ Feature: Simple Turns
 
         And the ways
             | nodes | highway | oneway |
-            | abc   | primary | no     |
-            | db    | primary | no     |
+            | abc   | primary | yes    |
+            | bd    | primary | yes    |
             | eb    | primary | yes    |
-            | fb    | primary | no     |
-            | bg    | primary | no     |
+            | bf    | primary | yes    |
+            | bg    | primary | yes    |
 
         When I route I should get
             | waypoints | route     | turns                          |
-            | a,d       | abc,db,db | depart,turn sharp right,arrive |
-            | a,f       | abc,fb,fb | depart,turn right,arrive       |
+            | a,d       | abc,bd,bd | depart,turn sharp right,arrive |
+            | a,f       | abc,bf,bf | depart,turn right,arrive       |
 
     Scenario: Right Turn Assignment Three Conflicting Turns with invalid - 3
         Given the node map
@@ -907,11 +907,10 @@ Feature: Simple Turns
     Scenario: Turn Lane on Splitting up Road
         Given the node map
             """
-
-            g       f
-
-                      h     e     c     d
-            a     b
+            g - - - f
+                     \
+                    . h - - e - - c - - d
+            a - - b _______/
                   i
             """