sql_io.py: cast(): Don't output warnings for errors that are stored in the errors table, because this clutters the log output unnecessarily. Warnings are still output when there is no errors table.

schemas/vegbien.sql: party: party_unique UNIQUE INDEX: Moved surname before givenname, middlename to enable the index to be used when just the person's last name is known. (Note that if the organization is not known, and explicit NULL would need to be put in for that field to use the index.)

sql_io.py: put_table(): DuplicateKeyException: Uniquifying input table to avoid internal duplicate keys: Include all join columns (including literal values) in the unique index, not just table columns, to encourage PostgreSQL to use the index in a merge join.

sql.py: distinct_table(): Support literal values as column expressions. Filter out untyped NULLs because the type unknown can't be indexed.

sql.py: add_index(): Support literal values as expressions

sql_gen.py: ensure_not_null(): Support Literal value inputs, which are passed through if not nullable

sql_gen.py: Added cast_literal()

sql.py: Added simplify_expr() and use it in parse_expr_col(). This will remove extraneous information from the condition that gets included in the errors table, so it's easy for the data provider to see what constraint is being violated as it applies to their data.

sql_io.py: put_table(): Handle CheckExceptions. This fixes a REMIB bug where some rows violated the specimenreplicate.specimenreplicate_required_key CHECK constraint, but there was previously no way to filter out just these rows so all rows were removed instead.

sql.py: Added map_expr()