Delegate Model#position to the Ordering object

Seems to make more sense rather than overriding id on the index views.
Add 1 to the position so we start from 1

Probably want to deal with this at the other end really. Anyway took a guess and it fixed stuff. W00p!
Don't rely on a title existing when displaying errors. Just use the class_name for now
Make ordering index shorter so it doesn't break the 62 character limit