Update Mongo read preference methods for 1.3.3 release

Fix parameter type for setReadPreference() methods, document getReadPreference() return value changes, and update version info for MongoCursor methods.

https://jira.mongodb.org/browse/PHP-666


git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@329170 c90b9560-bf6c-de11-be94-00142212c4b1