Add tests for node editorial process

I'll do this later.

This splits out each class into its own file, renames them, and adds some extra items to the node test to have some revision testing. It needs more work, but it's a start.

This adds some more tests to confirm that the revisions page loads when appropriate, and clarifies the old-vs-new titles.

This gets into reverting & deleting revisions. Woot!

Forgot to confirm that the meta tags had correctly changed after the revisions were fiddled with. And some other things.

Committed! Yay!