DB Utility improvements
 - Replaced driver methods _list_databases(), _optimize_table() and _repair_table() with properties
 - Added defaults for optimize_table() and repair_table() SQL strings (FALSE, as those are mostly MySQL-specific)
 - Added MSSQL/SQLSRV support for optimize_table() (actually rebuilds table indexes)
 - Switched public driver methods to protected
 - Improved CUBRID support for list_databases() as it used to only return the currently used database
 - Minor speed improvements
15 files changed