Makes YouTube thumbnail image corners square again
YouTube's new layout put rounded corners on everything and this stylesheet will make the corners square again for thumbnails and avatars. This will also square the corners of the mini-player and certain other elements which appear on the main pages of the site. If for some reason this script has stopped working, that just means YouTube has recently changed something and I'll fix it shortly.
If you don't want avatars to be square, then delete the entire "avatar selectors" line. If you wanted to square absolutely everything on the site, then you could replace all of the selectors in the code with a single * symbol - but I cannot guarantee that would be safe.
