[data] added properties nx/ny to Data object
[data] added routine to determine grid center position
[data] added routine to retrieve data of center position
[data] implemented option for get_center_data to return Data object
[data] bugfix cell area for get_center_data())
[data] added new option to get_deseasonalized_anomaly()
intermediate working dictconverter
intermediate working dictconverter
[util] added converter for dictionary to plain ASCII
[util] implemented test for append mode
[util] recursive tags for DICT2TXT converter working now