Multi adaptive vertex fitter

Implements the multi adaptive vertex fitter and all related required tools.

Core/include/Acts/Vertexing/IterativeVertexFinder.ipp

@@ -403,7 +403,7 @@ Acts::IterativeVertexFinder<bfield_t, input_track_t, propagator_t>::
         std::vector<input_track_t>&       perigeesToFitOut,
         std::vector<input_track_t>&       perigeesToFitSplitVertexOut) const
 {
-  int numberOfTracks(perigeeList.size());
+  int numberOfTracks = perigeeList.size();
 
   // Count how many tracks are used for fit
   int count = 0;