many changes and updates

- changed the wifi-estimation api
- adjusted test-cases
- worked on grid-bulding and grid-importance
- new walking modules
- fixed some minor issues

sensors/radio/WiFiGridNode.h

@@ -12,7 +12,7 @@ struct WiFiGridNodeAP {
 
 private:
 
-	static const int UNUSED_IDX = 255;
+	static const uint8_t UNUSED_IDX = 255;
 
 private:
 
@@ -25,10 +25,14 @@ private:
 public:
 
 	/** empty ctor */
-	WiFiGridNodeAP() : idx(UNUSED_IDX), rssi(0) {;}
+	WiFiGridNodeAP() : idx(UNUSED_IDX), rssi(0) {
+		int i = 0; (void) i;
+	}
 
 	/** ctor */
-	WiFiGridNodeAP(const int idx, const float rssi) : idx(idx), rssi(stretch(rssi)) {;}
+	WiFiGridNodeAP(const int idx, const float rssi) : idx(idx), rssi(stretch(rssi)) {
+		int i = 0; (void) i;
+	}
 
 
 	/** is this entry valid/used? */
@@ -70,13 +74,14 @@ private:
  */
 template <int maxAccessPoints> struct WiFiGridNode {
 
-
 	/** contains the 10 strongest APs measureable at this position */
 	WiFiGridNodeAP strongestAPs[maxAccessPoints];
 
 
 	/** ctor */
-	WiFiGridNode() {;}
+	explicit WiFiGridNode() : strongestAPs() {
+		;
+	}
 
 
 	/** get the maximum number of APs each node is able to store */