aggregation routine should accept dataframe concordance

[konstantinstadler]

currently it is not possible to use the aggreation routine with a panda dataframe concordance - it only accepts numpy arrays.

Plan:

• allow pd.dataframe (target classification in rows, source in header)
• check consistency with the io classifiction of the header, rearange if necessary
• convert to numpy array and use the existing routine

[konstantinstadler]

this is currently under development elsewhere