Feature: Edit order of photos in collection

[realpixelcode]

It should be possible to arrange the photos in a collection into a custom order.

[trwnh]

IMO a Collection should be chronological but it currently is not.

[cogdog]

Right now it's chronological, the oldest photo added is first. If anything, it should at least be reverse chronological.

Ideally, if I had my dreams, like Flickr Albums, an owner should be able to pick oldest first, newest first, random, or a manually sorted order.