Adapt to new js interface

book/test.js

@@ -1,9 +1,9 @@
-$(document).bind("bookReady", function() {
-    gitbook.bind("page.change", function() {
+require(["gitbook"], function(gitbook) {
+    gitbook.events.bind("page.change", function() {
         // do something
     });
 
-    gitbook.bind("exercise.submit", function() {
+    gitbook.events.bind("exercise.submit", function() {
         // do something
     });
 });