PhpFlickr 4.1.0

I've just tagged version 4.1.0 of my new fork of the PhpFlickr package. It introduces oauth support, and hopefully improves the documentation of the user authentication process. This release deprecates some old behaviour, but I hope it doesn’t break any. Bug reports are welcome!

There are some parts that are still not converted to the new request flow, but I’ll get to them next.