Add examples and consistency to MongoGridFS storage methods

https://jira.mongodb.org/browse/PHP-387


git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@329045 c90b9560-bf6c-de11-be94-00142212c4b1
Update MongoGridFS "see also" links and format as a list


git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@329046 c90b9560-bf6c-de11-be94-00142212c4b1