Word verification

I've turned on word verification for comments to Mr Porkpop, in order to avoid comment spam. Although I wasn't getting as much of it as some other people, I was getting enough that it was becoming annoying. So now, if you add a comment, you'll have to verify that you're a real person typing a real comment by typing in a string of random letters that are shown to you on the screen. Sorry about having to introduce this extra step, but it's become necessary.