The History Summary should "roll up" the edits to any given Thing

(User Story, Investigate , Priority: High, Test Status: No automated tests yet , Reported By Justin du Coeur, )
History, UX, User Interface
Summary: Currently, we spell out every little change in the History, which is completely unwieldy. Instead, I should see a single entry for "Justin created / edited Blah Blah Blah", with a button to drill in for more detail.
When you press the "Show Details" button, you would get the full entries.
Ideally, this change should be reflected in the client/server protocol -- we should have a concept of a "meta-entry" that encapsulates a bunch of entries. This would enormously cut the amount of traffic in displaying the History Summary.
Note that both the UI and the protocol need to take into account the possibility of multiple people editing at the same time. So a "meta-entry" isn't just a range (sadly), it's actually a list of history IDs.
Think about what to do if multiple people are editing the same Thing at the same time. The meta-entry should probably be centered on the thing, not the person, and shows the back-and-forth if you show the details.
The meta-entry should probably have a "Show Space" button of its own, which pops open the Space as of the last sub-entry.
Note that this story is not the be-all and end-all of improving the History Summary: we'll eventually want a higher-level timeline as well. But this is the highest priority, I think.