Make number of candidates a parameter

plugins/map_matching.hpp

@@ -130,7 +130,7 @@ template <class DataFacadeT> class MapMatchingPlugin : public BasePlugin
                     candidates,
                     last_distance/2.0,
                     5,
-                    20))
+                    Matching::max_number_of_candidates))
             {
                 return false;
             }

routing_algorithms/map_matching.hpp

@@ -70,6 +70,7 @@ namespace Matching
 typedef std::vector<std::pair<PhantomNode, double>> CandidateList;
 typedef std::vector<CandidateList> CandidateLists;
 typedef std::pair<PhantomNodes, double> PhantomNodesWithProbability;
+constexpr static const unsigned max_number_of_candidates = 20;
 }
 
 // implements a hidden markov model map matching algorithm