Some formatting adjustments and comment changes in Site Updates

I've been doing a little bit of minor tweaking which you may have noticed. Nothing major, except for in the comments section.

The good news is that comment thread depth is now unlimited. It doesn't stop at four levels like it has in the past, so you can continue your discussion on the same thread as long as you want without having to reply to the wrong comment as a workaround.

Because this would eventually shift things way too far to the right, I've eliminated things shifting beyond the first level by not showing icons on replies to replies and so forth. But there's now an indicator of who is replying to whom, so it should be pretty easy to keep things straight. We'll see how it works. Should be an improvement!