refactor of post-processing

- moves collapse into a dedicated set of functions / files
 - make collapse scenarios distinct (slight performance cost)
 - reduce verbosity for short name segments (now actually working, was supposed to do so before)

include/extractor/guidance/intersection_normalizer.hpp

@@ -83,7 +83,8 @@ class IntersectionNormalizer
                                      const IntersectionShapeData &source) const;
     IntersectionShapeData MergeRoads(const IntersectionNormalizationOperation direction,
                                      const IntersectionShapeData &lhs,
-                                     const IntersectionShapeData &rhs) const;
+                                     const IntersectionShapeData &rhs,
+                                     const double opposite_bearing) const;
 
     // Merge segregated roads to omit invalid turns in favor of treating segregated roads as
     // one.

include/extractor/guidance/sliproad_handler.hpp

@@ -65,6 +65,11 @@ class SliproadHandler final : public IntersectionHandler
                              const IntersectionViewData &first,
                              const IntersectionViewData &second) const;
 
+    // check if no mode changes are involved
+    bool allSameMode(const EdgeID in_road,
+                     const EdgeID sliproad_candidate,
+                     const EdgeID target_road) const;
+
     // Could a Sliproad reach this intersection?
     static bool canBeTargetOfSliproad(const IntersectionView &intersection);