Creating application.config attribute.

This creates less coupling between the handlers and the outer
IPython application.

IPython/frontend/html/notebook/handlers.py

@@ -416,7 +416,7 b' class AuthenticatedZMQStreamHandler(ZMQStreamHandler):'
     def open(self, kernel_id):
         self.kernel_id = kernel_id.decode('ascii')
         try:
-            cfg = self.application.ipython_app.config
+            cfg = self.application.config
         except AttributeError:
             # protect from the case where this is run from something other than
             # the notebook app:

IPython/frontend/html/notebook/notebookapp.py

@@ -187,6 +187,7 b' class NotebookWebApplication(web.Application):'
         self.cluster_manager = cluster_manager
         self.ipython_app = ipython_app
         self.read_only = self.ipython_app.read_only
+        self.config = self.ipython_app.config
         self.log = log
         self.jinja2_env = Environment(loader=FileSystemLoader(os.path.join(os.path.dirname(__file__), "templates")))