Playing around with Flickr support.

Hi there!

I know there were a couple of attempts to implement FlickrResourceOwner. This is another one. By no means this is a finished implementation. I just want your feedback on a couple of things:

 * Is it ok for `ResourceOwnerInterface::getUserInformation()` not to do any requests to `infos_url`? With Flickr we already get relevant information back with access token. I'm not sure if you have any kind of policy regarding this.
 * If above is OK, then should I implement another UserResponse object to accept parameters from constructor? Basically a simple value object. It makes no sense to use `UserResponseInterface::setResponse`.

Thanks in advance.