- Adding WifiDevice and Mobile. AccessPoint and Mobile are sub-classes
of WifiDevice.
- Measurement: link to Mobile and AccessPoint.
- Adding CalibrationMeasurement.
- ReferencePoint: add_measurement() and operators, link to
CalibrationMeasurement (not Measurement).
- Area and Waypoint : using pointers (not references) for attribute
setting.
- Deleted class ClientInfo (replaced by Mobile).