add pdo model
	modified:   config/errcode.php
	modified:   library/Bootstrap.php
	modified:   library/core/Config.php
	modified:   library/core/Controller.php
	modified:   library/core/Debug.php
	modified:   library/core/Dispatcher.php
	new file:   library/core/PDOModel.php
	modified:   library/core/Request.php
	modified:   library/core/Router.php
	modified:   library/core/Uri.php
	modified:   library/core/View.php
	modified:   library/fluent/BaseQuery.php
	modified:   library/fluent/CommonQuery.php
	modified:   library/fluent/FluentPDO.php
	modified:   library/fluent/FluentStructure.php
	modified:   library/fluent/InsertQuery.php
	modified:   library/fluent/SelectQuery.php
	modified:   library/fluent/UpdateQuery.php
	modified:   library/util/Ajax.php
	modified:   library/util/Cookie.php
	modified:   library/util/Pagination.php
	modified:   library/util/Session.php
	modified:   library/util/Validator.php