inputs/BRIT/specimen_flat/: translated multi-column filters with _join() to postprocessing derived columns, using the steps at wiki.vegpath.org/Adding_new-style_import_to_a_datasource#Translating-filters-to-postprocessing-derived-columns
inputs/BRIT/specimen_flat/: translated multi-column filters with _join() to postprocessing derived columns, using the steps at wiki.vegpath.org/Adding_new-style_import_to_a_datasource#Translating-filters-to-postprocessing-derived-columns