transactions && persistence

Howdy folks.

Since kev's started a persistent case repo, that's brought up the issue of
transactionality, and now that I'm examining all of our persitence needs,
it looks like I'll be changing a bit of the core, along with the entire
case-repo service, to better accommodate safe and valid transactions
while maintaining decent performance.

So, mostly just a heads-up that CVS might be periodically broken due to
checkpoint commits while I rework my data-access paths.

	-bob