import.stats.xls: Changed \/row (ms)" to "ms/row"

sql.py: mk_insert_select(): INSERT IGNORE: Used typed vars to store each column of the select query because the select query's column names are not known, so it would be unknown which record var column to use for each output column. (Add types so there are no unknown-type values that PostgreSQL will say can't be cast.)

sql.py: insert_select(): In ignore mode, always recover from errors

sql.py: mk_insert_select(): INSERT IGNORE: Implemented simple cursor loop that just inserts each row, without ignoring duplicate keys

sql.py: mk_insert_select(): Added ignore param to do an INSERT IGNORE equivalent operation. Added basic structure for INSERT IGNORE. Support embeddable queries without RETURNING columns (which is the case for most INSERT IGNORE queries).

sql.py: run_query_into(): Always set into.schema to None, so that table is created in the temp schema in debug_temp mode

sql.py: DbConn.DbCursor.execute(): Don't cache ADD COLUMN queries because the rest of the query must be unique in order to use caching

sql.py: add_col(): Don't ignore already-existing columns because sometimes name truncation causes collisions, requiring the caller to version the name. add_index_col(): Version the column name to avoid collisions.

sql.py: add_index(): Version index names to avoid collisions

sql.py: DbConn.DbCursor.execute(): Always cache structural changes, not just if they throw an exception