Modify _findPublished to accept a list of node-ids (to allow I18n search in 2.0)

This modification to the _findPublished method of the Node-Model allows people to use a custom search from a plugin (e.g. an i18n-search plugin), to pass an array of node-ids with the query parameters to the _findPublished method, which should be appended to the "normal" filter conditions.

This way, a list of the matching node-ids from the i18n table, can be appended with the matches of the nodes-table.

Even though this is to enable i18n search there might be other use-cases.