More web server stats

I spent some more time watching the ExifTool web server to see what was getting the most traffic. The most popular file is the "ExifTool Updates" RSS feed, which gets an average of about 2.3 hits per minute -- that's 100,000 hits per month (from more than 20,000 unique IP's). Due to the nature of RSS, I was worried about this file dominating our bandwidth, so I tried to keep it small (12 kB) and set its reload period to 90 minutes (for RSS readers that honour the TTL attribute). Good thing I did that.