sql_gen.py: Col.__str__(): Truncate any table name using concat() to ensure that the full column name is included in the string

strings.py, sql_gen.py: Renamed add_suffix() to concat() to reflect that this is a fixed-length replacement for +

sql.py: put_table(): Moved MissingCastException to the top of the exceptions list because it's more of a core exception than the others, and will be raised before any rows are even inserted

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