#338 Add new PHP functions to documentation

[Jira Trac]

As I know, some new functions have been added to 9.0.0 PHP driver. Users can never find out about them unless we have their descriptions in our [PHP Manual|http://www.php.net/manual/en/book.cubrid.php]. Please add them always and reflect any API change as well.

Also, please mention any change/improvement/new feature in release notes.