use App.instance() in launch_new_instance

This way later calls to App.instance() will return the running
application, whereas calling App() would create an isolated
Application object.

IPython/frontend/terminal/ipapp.py

@@ -345,10 +345,8 b' def load_default_config(ipython_dir=None):'
 
 def launch_new_instance():
     """Create and run a full blown IPython instance"""
-    app = TerminalIPythonApp()
+    app = TerminalIPythonApp.instance()
     app.initialize()
-    # print app.config
-    # print app.profile_dir.location
     app.start()