Fixed history not update if note have no content and lz-string version mismatch

bower.json

@@ -31,6 +31,7 @@
     "socket.io-client": "~1.3.7",
     "viz.js": "~1.3.0",
     "js-yaml": "~3.4.6",
-    "to-markdown": "~1.3.0"
+    "to-markdown": "~1.3.0",
+    "lz-string": "~1.4.4"
   }
 }