[Tilesathome] t at h server performance improvements

[Christopher Schmidt]

With the help of Martijn, this morning we did some optimization to the
t at h server -- specifically, to increase performance with regard to blank
tile handling. The end result is that we're now processing tiles at a
similar rate to the rate we were more than a month ago, and it appears
that we may be in a position to cope with additional client load. Many
thanks to Martijn for his help. (Also, I think I'm just going to call
him kleptog from now on -- Martijn is too hard for my silly Americanized
fingers!)

So, if you've got a render farm that you've been letting sit idle -- let
her rip. If you want an account and you don't have one, drop an email to
myself or ben with a username, and we'll get you set up.

Thanks,
-- 
Christopher Schmidt
MetaCarta