TNL-784: Scroll  to note and open it

**Ticket:** https://openedx.atlassian.net/browse/TNL-784

**Acceptance criteria:**
When the unit is opened from a link from the View All Notes view, the note that was clicked from should be scrolled into view and should be opened for viewing on the unit. To close the note, you can click outside of the note pop-up. Orphaned notes shouldn't have this behavior.

**Sandbox:** http://jmclaus.m.sandbox.edx.org

@polesye @tymofij @explorerleslie Please review.
@jmclaus Could you add a test to make sure that this event is unbound.
You use `_.bind` in `subscribe` and `unsubscribe` methods. `_.bind` method returns new function with appropriate context. So, callback function passed in `subscribe` !=  callback function passed in `unsubscribe`. Am I wrong?