Change check for enabled to is(':not([disabled])')

This is a more accurate check. The previous check was preventing me from moving forward in the tour. See the explanation copied from jQuery documentation on :enabled.

"Although their resulting selections are usually the same, :enabled selector is subtly different from :not([disabled]); :enabled selects elements that have their boolean disabled property strictly equal to false, while :not([disabled]) selects elements that do not have a disabled attribute set (regardless of its value)."

Changing to :not([disabled]) fixed the issue for me.
Merge pull request #1 from timkindberg/master

Change check for enabled to is(':not([disabled])')