Added main app view controller
Make async request to Flickr API and receive XML
Parse Flickr response XML into NSObjects, root object is FlickrFeed which contains 0 or more FlickrEntry objects
Change ViewController from a UIViewController to a UICollectionViewController and implemented the required protocols
A little bit of reformatting and code cleanup
Have the cell make an async request for the thumbnail image
Basic working collection view loaded with thumbnails from Flickr.