Fix bugs in ignored column selection logic.
Fix bugs in ignored column selection logic.

UUID columns had piled on extras.  Now use a map to prevent duplicates.

Also, simplify/unify ignored_cols and ignored_cols_by_name up front.
UUID columns broke that path, as well.

calvingit21/h2o-2,h2oai/h2o-2,100star/h2o,calvingit21/h2o-2,elkingtonmcb/h2o-2,111t8e/h2o-2,elkingtonmcb/h2o-2,111t8e/h2o-2,100star/h2o,elkingtonmcb/h2o-2,vbelakov/h2o,rowhit/h2o-2,elkingtonmcb/h2o-2,eg-zhang/h2o-2,h2oai/h2o,rowhit/h2o-2,100star/h2o,h2oai/h2o,111t8e/h2o-2,elkingtonmcb/h2o-2,h2oai/h2o-2,calvingit21/h2o-2,rowhit/h2o-2,calvingit21/h2o-2,h2oai/h2o,eg-zhang/h2o-2,elkingtonmcb/h2o-2,h2oai/h2o-2,100star/h2o,rowhit/h2o-2,calvingit21/h2o-2,vbelakov/h2o,rowhit/h2o-2,vbelakov/h2o,111t8e/h2o-2,rowhit/h2o-2,elkingtonmcb/h2o-2,calvingit21/h2o-2,eg-zhang/h2o-2,h2oai/h2o-2,eg-zhang/h2o-2,eg-zhang/h2o-2,rowhit/h2o-2,h2oai/h2o-2,111t8e/h2o-2,vbelakov/h2o,rowhit/h2o-2,rowhit/h2o-2,vbelakov/h2o,111t8e/h2o-2,111t8e/h2o-2,eg-zhang/h2o-2,h2oai/h2o,h2oai/h2o,vbelakov/h2o,h2oai/h2o,vbelakov/h2o,100star/h2o,h2oai/h2o,eg-zhang/h2o-2,100star/h2o,h2oai/h2o,eg-zhang/h2o-2,elkingtonmcb/h2o-2,eg-zhang/h2o-2,h2oai/h2o-2,111t8e/h2o-2,111t8e/h2o-2,calvingit21/h2o-2,h2oai/h2o-2,calvingit21/h2o-2,111t8e/h2o-2,100star/h2o,eg-zhang/h2o-2,h2oai/h2o,rowhit/h2o-2,elkingtonmcb/h2o-2,h2oai/h2o,elkingtonmcb/h2o-2,h2oai/h2o-2,vbelakov/h2o,100star/h2o,100star/h2o,calvingit21/h2o-2,vbelakov/h2o,vbelakov/h2o,calvingit21/h2o-2,h2oai/h2o-2,h2oai/h2o-2