Auto-stop cursor.observe and cursor.observeChanges #1
Description
It would be convenient if cursor.observe/observeChanges would also auto-stop when the component is destroyed.
Come to think of it, it might be a wild goose chase to track down and monkey patch all the places where this would be useful. Perhaps it is possible to find a way to either automatically wrap the whole component in a Tracker.Computation or to patch Tracker.onInvalidate somehow.