some fixes [multithreading,..]

needed interface changes [new options]
logger for android
wifi-ap-optimization
new test-cases

grid/walk/v2/modules/WalkModule.h

@@ -9,6 +9,22 @@ struct WalkState {
 	/** current position within the grid (-> in cm!) */
 	GridPoint position;
 
+	/** nested struct to prevent name clashes */
+	struct Distance {
+
+		/**
+		 * for every walk, the walker is given a desired distance
+		 * however, the walking distance depends on the grid size and can
+		 * therefore never be reached exactly. therefor we track the
+		 * error between desired and walked distance to ensure "in average"
+		 * the walked distance is correct
+		 */
+		float error_m;
+
+		Distance() : error_m(0) {;}
+
+	} distance;
+
 	/** ctor */
 	explicit WalkState(const GridPoint& position) : position(position) {;}
 
@@ -23,7 +39,7 @@ template <typename Node, typename WalkState> class WalkModule {
 public:
 
 	/** update the given WalkState before starting the walk. e.g. based on sensor readings */
-	virtual void updateBefore(WalkState& state) = 0;
+	virtual void updateBefore(WalkState& state, const Node& startNode) = 0;
 
 	/** get the probability p(e) from curNode to potentialNode */
 	virtual double getProbability(const WalkState& state, const Node& startNode, const Node& curNode, const Node& potentialNode) const = 0;