More bugs fixed

Greg Reinacker discovered a bunch of bugs in my comment system. I was terminating my HTTP headers early, which caused the CGI handler to send 2 messages back to the browser. Second, my comment handler accepts no markup. I've fixed the former and bandaided the latter until I get around to implementing the Comment API. So a newline in the comment form will convert to a <br> now.

— Gordon Weakliem at permanent link