Add ability to delete updates from frontend

- Fixes #47 

* This adds model, collection, and a (list) view associated with the updates.
* When a Stand is fetched, it fetches its associated updates and stores them as a local variable (`this.updates` from the Stand model perspective).
* When a Stand page is accessed, the router builds the StandView and then builds the UpdatesView list (which is the set of rows that go in the table of updates).
* In the initialization of the UpdatesView we tell the UpdatesView to listen to its collection of updates (which, *importantly*, is the same collection that was fetched by the Stand model which in turn was fetched by the `show()` function in the router; note this is a different object than might be accessed through the app.stands collection, and for event passing to work you have to ensure that you're passing events to the same events that you intend to then listen to later).