Faster load times for discussions

I mentioned last week that I made a few changes to improve performance across the site. I continued with some additional changes the past few days, this time focused on comments. The most noteworthy changes are...

1. I improved the code for fetching threaded comments. This will reduce the load time for any page with comments (giveaways, discussions, tickets), but you'll see the largest impact on discussions with a high number of comments.
2. The pagination system for comments has been revised, which also helps with load times. The "Last" page button will now link to "page=last". Previously, users would write scripts linking to "page=99999" and the site would display the last page of comments. If you do that now, it'll display no results. Instead, if you want to be redirected to the last page of comments, link to "page=last".
3. I also worked a bit on the messages page, so you'll see some improvement there. I won't call it "fast" (especially if you haven't opened it in a while and it needs to cache your data), but it's quicker than before.

In terms of numbers, discussions with a small number of comments were taking 0.07s to generate last week, and now they're down to 0.02s. Large discussions (15,000+ comments) are seeing significant improvement, going from over one second down to the same 0.02s.