DB module and diagnose update

This version introduces multiple enhancements:

fixed handling of query model for pdo connection
added simple query to diagnose class

Details of additions/deletions below:
--------------------------------------------------------------

Added:      /Lib/Core/Db/Helper/Pdo/Mysql.php
            -- Added --
                handle mysql queries for pdo connection type

Modified:   /Lib/Core/Db/Helper/Mysql.php
            -- Updated --
                $_options, changed default connection type to mysqli
                _query, changed from private to protected, removed pdo error handling
                _setCharset, documentation changed

Modified:   /Lib/Core/Shell/Helper/Diagnose.php
            -- Added --
                _databaseAccess to execute simple query to database
            -- Updated --
                _getConnections, added handling of simple queries
                _connect, removed connection object name (now use the same name as class name)

Modified:   /Lib/Core/Db/etc/config.ini
            -- Modified --
                changed version from 0.8.2 to 0.9.0

Modified:   /Lib/Core/Shell/etc/config.ini
            -- Modified --
                changed version from 0.4.0 to 0.5.0