paper: don't keep the menu affixed to the top
This makes scrolling slow and causes browsers to use a lot of CPU time.
<!-- quirksmode -->
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<link rel="icon" href="{staticurl}hgicon.png" type="image/png">
<meta name="robots" content="index, nofollow" />
<link rel="stylesheet" href="{staticurl}style-paper.css" type="text/css" />