Renamed view.js -> controller.ts, album_view -> album_controller.ts, photo_view->photo_controller.ts
Split Album between AlbumView and AlbumController
Moved onKeydown() to controller.
Split Photo between PhotoController and PhotoView.
Pushed more album logic in PhotoController.
Added cache div to PhotoView
Removed PhotoView::load() and put PhotoView::loadItem() in its place.
Re-added prefetch() feature to PhotoView and PhotoController.
Refactoring. Split views into controllers and views.
Merge branch 'dev/slideshow' into develop