Modifying collapsible fieldsets on the node add/edit form to initially better present information

This issue is separated from #472126: D7UX: Move buttons to right area, add content and meta selector → so as to avoid putting the issue into a "giant, unreviewable patch" state. This patch changes the fieldsets on the "Meta" tab created in that issue to pseudo-collapsible fieldsets that give some information on the current state of the settings, and provides the user with an option to change the current settings. It does not fully represent the mockup created at http://d7ux.org/content - I tried to implement it as cleanly and simply as possible, without undo changes to the underlying code. I think that the interface I've created captures the essence of the idea presented at http://d7ux.org/content, but if the community feels I've left out an important component of the proposal, I would be happy to reroll a patch including it.

Disclaimer: I had to do some version control black magic to roll this patch, so I apologize if there are any mistakes in what is included or not in this patch.