Add Photo gallery pagination to Photo News

This is a branch off of `caridy/photo-search`.

It adds a Photo view for a single image (like Flickr's image viewer) and lets you paginate between different photos, by clicking on left or right arrows.

There's currently an issue with this view that was discussed with @imalberto, which is also an issue with the search functionality.

Going from `/photos/1/` to `/photos/2/` does not trigger a page re-render, because the application is unable to determine that the view has changed.  Inside of the micro-library, the views are considered to be the same due to how `app.page` creates them.  They are not re-rendered because the micro-library can't differentiate between whether a page has been newly loaded and bootstrapped, or whether the model has changed and the view needs to be re-rendered.

The same situation currently occurs with `/search?q=miami` to `/search?q=sunnyvale`.  

This is something that we should probably discuss before moving on to our next application - it's something that's definitely going to come up again.