Added droneId to command server. droneId is set at the same time as sessIdDrone when setSessId is received from central station.
Renamed command UnconnectFromDrone to Disconnect.
Replaced UnsetSessId command and UnconnectFromDrone by Disconnect command. The disconnect command will kill the session for the sessId value in the header.
Removed handleUnsetSessId in packet handlers.
Renamed handleUnconnectFromDrone to handleDisconnect in packet handlers.
Added function deleteSession to central server.
Added function disconnectFromDrone() in command server.
Redefined toString() for Disconnect command.
Implemented handle disconnect command for central station.
Added test call to disconnect from command panel when command server status changed to connected.