added measurement grouping for beacons

had to change the parameter boundaries of the wifi optimizer to be able to use it for bluetooth... this should be refactored to something more generic..
some minor changes in ble

sensors/beacon/model/BeaconModel.h

@@ -15,6 +15,8 @@
 #include "../BeaconMeasurement.h"
 #include "../../../geo/Point3.h"
 
+#include "../../../data/XMLserialize.h"
+
 #include <vector>
 
 /**
@@ -23,14 +25,17 @@
  * the model is passed a MAC-address of an AP in question, and a position.
  * hereafter the model returns the RSSI for this AP at the questioned location.
  */
-class BeaconModel {
+class BeaconModel : public XMLserialize {
 
 public:
 
 //	/** get the given access-point's RSSI at the provided location */
 //	virtual float getRSSI(const LocatedAccessPoint& ap, const Point3 p) = 0;
 
-	/** get a list of all APs known to the model */
+    /** dtor */
+    virtual ~BeaconModel() {;}
+
+    /** get a list of all APs known to the model */
     virtual std::vector<Beacon> getAllBeacons() const = 0;
 
     /**
@@ -43,13 +48,13 @@ public:
     virtual void updateBeacon(const BeaconMeasurement beacon) = 0;
 
 
-	/**
-	 * get the RSSI expected at the given location (in meter)
+    /**
+     * get the RSSI expected at the given location (in meter)
      * for an beacon identified by the given MAC.
-	 *
+     *
      * if the model can not predict the RSSI for an beacon, it returns NaN!
-	 */
-	virtual float getRSSI(const MACAddress& accessPoint, const Point3 position_m) const = 0;
+     */
+    virtual float getRSSI(const MACAddress& accessPoint, const Point3 position_m) const = 0;
 
 };