schemas/util.sql: added explain2str()

schemas/util.sql: added explain2table()

schemas/util.sql: added explain()

schemas/vegbien.sql: taxonlabel_update_ancestors(): don't create a performance-intensive nested transaction (EXCEPTION block) for each INSERT, because there should no longer be duplicate ancestors, so it's OK to abort the whole transaction if this assertion fails

bugfix: schemas/vegbien.sql: taxonlabel_update_ancestors_on_{insert,update}(): only use either the matched taxon's ancestors or the parent's ancestors, to avoid issues related to duplication between these two ancestors lists. this also fixes a bug where the 2nd taxonlabel_update_ancestors() call assumes that the existing ancestors are for the old parent, when in fact they have actually just been set to those for the new matched taxon (which horribly confuses taxonlabel_update_ancestors()).

schemas/vegbien.sql: _taxonlabel_set_parent_id(): just use a plain UPDATE statement, to avoid the significant parsing and stringification overhead of EXECUTE and quote_nullable(). it is not clear that EXECUTE is actually necessary to avoid caching the query plan, because the cache should be invalidated automatically when the table's ANALYZE statistics are regenerated.

schemas/vegbien.sql: removed unused function _taxonlabel_set_matched_label_id(), which refers to obsolete fields

schemas/vegbien.sql: synced to DB (the view renderer apparently changed the text of a view)

backups/TNRS.backup: saved copy backups/TNRS.2013-11-18.backup

bugfix: bin/import_all: run in errexit mode, so that if the user cancels reinstalling of the import schema, the script will then abort instead of continuing and using the wrong schema