Implement step error handling

[mattcasters]

Probably by moving everything to multiple PCollections, one for data, one for errors.

[mattcasters]

This should be a question of capturing the error rows in the StepFn rowListener

            rowListener = new RowAdapter() {
              @Override public void rowWrittenEvent( RowMetaInterface rowMeta, Object[] row ) throws KettleStepException {

                // if (infoSteps.size()>0 && resultRows.size()==0) {
                //  System.out.println( ">>>>>>>>> CAPTURE ROW: "+rowMeta.toString());
                // }
                resultRows.add( row );
              }

              @Override public void errorRowWrittenEvent( RowMetaInterface rowMeta, Object[] row ) throws KettleStepException {
                errorRows.add(row)
              }
            };```