sarissa.js patch - support for Firefox 3.6

[nelg]

Please apply the following patch to sarissa.js.

This is to support firefox 3.6.. which otherwise never shows the main window.

             * <li>3 == INTERACTIVE,</li>
             * <li>4 == COMPLETED</li></ul>
             */
-            XMLDocument.prototype.readyState = 0;
+            try {
+                XMLDocument.prototype.readyState = 0;
+            } catch(e) {
+                // XXX on some browsers (Firefox 3.6 at least) this fails,
+                // however I think this is rarely a problem so we just
+                // ignore it here...
+            };
             /**
             * <p>Emulate IE's parseError attribute</p>
             */