Add update script to adjust view mode selection for extras field

So I didn't see an easy way to auto add based on the view display so instead I just defaulted the extras field to be hidden. Workflow I was thinking of is

1. You enable a new content type to be in book
2. It should then be the site admins responsibility to set where that book navigation should appear

Thoughts?

That looks pretty good, though I have not tested it. I think it would be worth including in the release.

Automatically closed - issue fixed for 2 weeks with no activity.