Option to display list as links

Currently the list that is a simple list. It was requested in issue #1296218: Commerce Checkout Progress

...how about making those links? Or would that cause problems with the checkout flow?

I can see having some of the list be links and others being simple list items. We might want to let the user go back by clicking, but we don't want to let the user click too far ahead. It would be a little silly to let them jump directly to the order confirmation screen.