sql.py: DbConn: Don't always autocommit in debug_temp mode, because this could cause autocommit mode to be turned on when the user does not expect it

bin/map: connect_db(): Autocommit in commit mode to avoid the need for manual commits. This should also reduce the time that table locks are held, to avoid unnecessary contention when multiple processes are trying to insert into the same output table. (The program always uses nested transactions to support rollbacks, so there is no problem autocommitting whenever a top-level nested transaction or top-level query completes.)

sql_gen.py: Removed TempFunction because that functionality is now provided by DbConn.TempFunction()

sql.py: Use new DbConn.TempFunction()

sql.py: DbConn: Added TempFunction()

sql.py: Use new DbConn.debug_temp config option to control whether temporary objects should instead be permanent

sql.py: DbConn: Added config option debug_temp

sql.py: function_exists(): Fixed bug where trigger functions needed to be excluded, since they cannot be called directly

sql.py: Added function_exists()

sql_gen.py: Made Function an alias of Table so that isinstance(..., Function) will always work correctly