Implement a cross machine login so that user is automatically logged
into the Wiki when clicking on the My Wiki's link. Works like this: * The My Wiki's link points to new page, gotowiki.php3, on boss. * The gotowiki page looks for a new cookie in the user's browser which holds a key (the usual random data run through md5). * If the key does not exist, generate it and store it in the user browser (expires when browser is closed or emulab login times out). Also invoke backend script wikixlogin, which will send the key over to the wiki server (via ssh), which will write the key into a file named by the user account. * The user's browser is redirected to the wiki server's login script (twiki/bin/newlogon), but instead of username and password, we send over username and key (as well as redurl= parameter which is the page on the wiki server to redirect to later). * The new login script looks for this case, and opens the file named by the user and compares the key it gets with what is in t...