added new helper methods to work with ground-truth

made some assertions optional [i know what i am doing!]

sensors/radio/model/WiFiModel.h

@@ -14,6 +14,9 @@ class WiFiModel {
 
 public:
 
+	/** dtor */
+	virtual ~WiFiModel() {;}
+
 //	/** get the given access-point's RSSI at the provided location */
 //	virtual float getRSSI(const LocatedAccessPoint& ap, const Point3 p) = 0;