added several grid-walks

added new helper methods/classes (e.g. for heading)
new test cases
optimize the dijkstra
cleanups/refactoring
added timed-benchmarks to the log
many more...

grid/walk/GridWalkState.h

@@ -0,0 +1,21 @@
+#ifndef GRIDWALKSTATE_H
+#define GRIDWALKSTATE_H
+
+#include "../../geo/Heading.h"
+
+template <typename T> struct GridWalkState {
+
+	/** the user-node this state resides at */
+	const T* node;
+
+	/** the current heading */
+	Heading heading;
+
+	/** empty ctor */
+	GridWalkState() : node(nullptr), heading(0) {;}
+
+	/** ctor with user-node and heading */
+	GridWalkState(const T* node, const Heading heading) : node(node), heading(heading) {;}
+
+};
+#endif // GRIDWALKSTATE_H