Add a license_id argument to file upload

[ianengelbrecht]

This is a suggestion for the API itself, rather than this node client, but it would be good to be able to set the license for an image in the upload.

So here: https://www.flickr.com/services/api/upload.api.html
...it would be good to have a license_id argument, matching obviously with ids from flickr.photos.licenses.getInfo.