Headsup: config changes

[netllama]

@bluegreenkayak contacted me offline to report that these changes were accidentally blocking her ability to create a new thread with a lot of images.  Apparently linking out to a huge number of external images (such as Flickr) gets treated as one connection per image, which can quickly exceed the threshold for detecting an attack.

I've tweaked the config a bit, and it should hopefully fix this problem.