[WIP] Notes page.

@tymofij , @olmar , @jmclaus please review.

sandbox: http://polesye.m.sandbox.edx.org/courses/edX/DemoX/Demo_Course/edxnotes
> Here are 4 identical patches. Can you use decorator? And then create another test for ImproperlyConfigured?

Just 2 patches are similar. So, I do not see the reason to do that.