Use slave servers for statistics module

I think we can safely use slave queries for the stats module, too, since it's mostly aggregate data. A few seconds lag is fine.

I have left one query running against the Master. It's the "recent hits" page. That's a fairly fast query and is the only one that might need to be more up to date for some reason. If not, it's trivial to move it over as well.

And once again, oh yeah, whitespace. :-(