* speed up hop-to-hop calculations

* better and faster trip clustering: trip tries
* add --write-colors to extract line colors from OSM data
* refactor config parameter names, update default pfaedle.cfg
* add --stats for writing a stats.json file
* add --no-fast-hops, --no-a-star, --no-trie for debugging
* general refactoring

src/util/graph/BiDijkstra.cpp

@@ -0,0 +1,7 @@
+// Copyright 2017, University of Freiburg,
+// Chair of Algorithms and Data Structures.
+// Authors: Patrick Brosi <brosi@informatik.uni-freiburg.de>
+
+#include "util/graph/BiDijkstra.h"
+
+size_t util::graph::BiDijkstra::ITERS = 0;