sql.py: put_table(): Return just the name of the table where the pkeys are made available, since the column name in that table now equals the pkey name

sql.py: mk_insert_select(): embeddable: Make the column returned by the function have the same name as the returning column

db_xml.py: put_table() Use new sql.put_table()

sql.py: Added put_table()

sql.py: Added clean_name(). Use it where needed to make an escaped name appendable as a string.

sql.py: Added with_parsed_errors() and use it in try_insert()

sql.py: insert_select(): into != None: Fixed bug where cacheable was not passed through to DROP TABLE's run_query(), even though it was passed through to CREATE TABLE AS's run_query()

db_xml.py: put_table(): Place pkeys in temp table

sql.py: mk_insert_select(): Document that embeddable will cause the query to be fully cached, not just if it raises an exception. insert_select(): into != None: Pass recover and cacheable through to each run_query()

sql.py: insert_select(): Support placing RETURNING values in temp table