fix tab hash / url behavior

clicking tabs sets hash, loading hash url implies tabs

IPython/frontend/html/notebook/static/tree/js/main.js

@@ -70,5 +70,16 b' $(document).ready(function () {'
         IPython.notebook_list.handelFilesUpload(event,'form');
     });
 
+    // set hash on tab click
+    $("#tabs").find("a").click(function() {
+        window.location.hash = $(this).attr("href");
+    })
+    
+    // load tab if url hash
+    if (window.location.hash) {
+        $("#tabs").find("a[href=" + window.location.hash + "]").click();
+    }
+
+
 });