I should be able to define an all-or-nothing Submit Form

Summary: This is a pretty big deal, since it isn't the way Querki usually works. But it's often desireable, and is needed for the Arisia project.

The notion here is that I can have an Editor with a Done button that means Submit in the classic sense: nothing is saved until you press that button. At that point, everything is validated, and the edit is all-or-nothing.

This is actually most important for Create, more than Edit: the Thing doesn't get created until everything is ready and validated.