[development] Requiring node revisions

[Nedjo Rogers]

> ... all for the sake of a couple of checkboxes.

Of course, it would be an easy form_alter in contrib to turn the "create new 
revision" checkbox into a #value type form element and enforce revisions.

Alternately, in core, we could create a "node_force_revision" variable. If 
set to 0, behaviour is as at present. If set to 1, the 'revision' form 
element is passed as a #value.