TNL-931: Eventing for Student Notes.

@mulby, @jmclaus  please review.
> I still don't see where async is set to false... even with preventDefault, won't we just end up calling $.ajax with async == true?

We do not need `async == false` here. It redirects to the appropriate page just after getting response from the server. We're using promises (https://github.com/edx/edx-platform/blob/anton/edxnotes-events/lms/static/js/edxnotes/views/note_item.js#L53). There is appropriate test https://github.com/edx/edx-platform/blob/anton/edxnotes-events/lms/static/js/spec/edxnotes/views/note_item_spec.js#L69

> Timeout sounds like a good idea, maybe we should have a default timeout in Logger.js?

Yes, it's a good idea. What value for the timeout do you prefer? 2, 3 seconds?