Replaced string comparison with == by string comparison with equals
Added parent header to csv.
Added error handling for the case that a student dataset does not
contain any parent information.
Inserted parent-testdata into csv.
Changed header name "Erz1StraßeNr" to "Erz1StrasseNr"
Added check for NumberFormatException to check if the postalcode is a
number. Changed postalcode in csv from "Test" to "1".