Store validationError on the BZGFormCell as an NSError, and then display it in the info cell
Add configurable flag for whether or not the BZGFormViewController should show validation cells
This seems to work, but causes tests to fail (unequal objects), so it's sort of weird and I don't trust it. Rely on a more traditional map.
Publicize navigateToDestinationCell
Add method for getting firstWarningCell