rate limiter installed

[mysq...@gmail.com]

I just pushed an update to prevent queries being run from a row more
than once in two seconds. This is part of our recent push to chase
down the occasional high-contention queries that have been giving us
problems, without messing with gameplay. It shouldn't interfere with
anyone, but if it causes unforeseen problems, let me know.

By the way, we're at about 2/3 the request level of yesterday, and
quotas are looking *way* better. That hopefully means Google's
optimization suggestions are working. (What kind of free web host
gives you phone support on your own code, by the way? Seriously?)

This means we should soon be able to combine all the shards again
(won't that be fun?), and then we can finally get to those balance
issues. We're listening, I promise.

--Jack