Try to fix some memory leaks. I think cursors don't leak any more
but I've had no luck with connections. If you close your connections
you should be fine, even if you don't close your cursors.
MySQL-5.0).
Mapped some new error codes to DataError, which has always existed,
but never had anything mapped to it.
Cleaned set_character_set() a bit.
Added new connection option sql_mode and correspond set_sql_mode()
method.
* Remove version_info from metadata before calling setup() to avoid
complaints
* Fix cursor.callproc() as good as can be fixed.
* Improve/fix various tests for stored procedures.
