Allow PodsAPI->load_object() to request specific parameters

[jamesgol]

Could be either via a passed param or a filter.

Currently returns:

        $object = array(
            'id' => $_object[ 'ID' ],
            'name' => $_object[ 'post_title' ],
            'code' => $_object[ 'post_content' ],
            'type' => str_replace( '_pods_', '', $_object[ 'post_type' ] ),
            'slug' => $_object[ 'post_name' ]
        );

Plus all of the post_meta associated with the ID.

Was looking to also get the post_modified date, can work around the issue but might be nice for the future.