sql.py: DbConn.with_savepoint(): Always release savepoint, because after ROLLBACK TO SAVEPOINT, "The savepoint remains valid and can be rolled back to again" (http://www.postgresql.org/docs/8.3/static/sql-rollback-to.html). Moved `self._savepoint -= 1` to the main try block's new finally block.

sql.py: put_table(): Lock output table right before, and in the same nested transaction as, the insert statement that needs lock, so that it is not released in a prior autocommit and is held for as little time as possible

db_xml.py: put_table(): Removed no longer needed commit param

bin/map: Removed rollback() call before closing the connection because PostgreSQL does this automatically

csv2db: Log inserts with log_level=5 so they are not shown for verbosity 4, which is used to see the savepoints and autocommits

Removed unnecessary db.db.commit() calls because commits are now done automatically by DbConn's autocommit mode

sql.py: DbConn.do_autocommit(): Output the "Autocommitting" debug message with level=4 so that it doesn't clutter up the logging output for normal verbosities

DbConn: autocommit mode defaults to True so that all scripts get the benefit of automatic commits

input.Makefile: Staging tables: import/install-%: Include the table name in the log file name so that successive tables for the same datasource don't overwrite the same log file

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