A small change to the comments section

With great reluctance, I have added 'word verification' to the comments section. This means that if you want to post a comment, you will have to type in a word given on the page to verify that you are not a machine posting but a human being (or a reasonable approximation thereof). I hate having to do this, although it is only a minimal nuisance for posters, but the spam comment from earlier today is one spam comment too many. I get enough of this crap in my inbox without adding to it on the blog.