Add a note about messages
Don't show albums with no photos in the thumbnail grid view

Since otherwise, what do we use as the album cover?

This has the nice side effect of hiding these albums away a
bit.
Add support for messages on actions, and add a couple of messages
Expose album deletion option
Add messages for all other significant actions

Annoyingly, these are difficult to test, because the
RequestFactory doesn't use the middlewares, so requests
don't have all the things they need.
Add tests that messages are set correctly

This required adding a fake message storage object to the
request object, since RequestFactory itself doesn't support
any middleware, including all the stuff that adds support
for messages.
Add a back button on the album deletion page
Rename delete.html to deletion.html for consistency
Remove unnecessary semi-colon
Include links to childrens' profile pages in the album detail
Horizontally align tags on photo pages
Unregistering children doesn't remove them from photos
Use the short traceback for display test failures
Hide away hard-coded album location

At some point we'll need to cache location information in
the model, but until we do that, we probably don't want to
spin over all photos in the album fetching location
information.
Separate off album attributes to its own template
Separate off photo thumbnails to their own template
Rename the photo thumbs parameters to allow template reuse
Add missing file header
Add a convenience method for getting all a user's favourite photos
Allow viewing favourites from any album