`MappingIterator` returns `List` or `Map` depending on `CSVSchema.withHeader()`

If CSVSchema.withHeader == true i must do:

` final Map line = (Map) mappingIterator.nextValue();`

If CSVSchema.withHeader == false i must do:

` final List line = (List) mappingIterator.nextValue();`

My use-case is: I have only one Class in which i parse CSV and this class can be configured to read the csv with header or without header (boolean-flag). For me it would be better if the MappingIterator always returns the same result-type (either a list or a map). Its not necessary, but would make things easier for me because now i need to cast the type like above, which looks a bit unsafe and is marked as yellow-warning in Eclipse-IDE.