sql.py: DbConn.DbCursor.execute(): If not using params, escape the query using strings.esc_for_mogrify() in case any literals contained "%"s

strings.py: Added esc_for_mogrify()

sql.py: create_table(): Add indexes on all non-pkey columns, unless turned off or deferred using new param col_indexes

csv2db: Add column indexes on errors table. Use typed_cols and `.to_Col()` to iterate over columns to add indexes on, for the main and errors tables.

sql.py: Added track_data_error(). put_table(): ignore(): Take extra e param for the exception. Use track_data_error() to store the invalid value in the errors table.

sql_gen.py: Join.to_str(): Add newline before and after right table if it's been renamed (and therefore takes up multiple lines)

exc.py: ExceptionWithCause: Store the cause in an instance variable for later use

sql.py: mk_track_data_error(): Rename the errors_table to make the generated SQL less verbose

sql.py: mk_insert_select(): Run sql_gen.remove_table_rename() on table to get just the actual name in the DB

sql_gen.py: Added remove_table_rename()