[WIP] Views hooks 

Setting up an early PR to get some feedback on views hooks.

Proposed hooks API:

```javascript

Balanced.registerSectionHook("customer/details", function(controller, container) {
  var view = SomeView.create();
  container.insertAt(2, view);
});

// These will use `registerSectionHook` to append the view to the container
Balanced.registerSectionView("customer/details", function(controller) {
  var view = SomeView.create();
  // do stuff with the view
  return view;
});

Balanced.registerSectionView("customer/details", SomeOtherView, {
  modelBinding: "controller.model"
});

Balanced.registerSectionView("customer/details", AnotherView);


Balanced.registerPageHook("customer", function(page) {
  page.registerSectionHook("details", .......); // Calls Balanced.registerSectionHook("customer/details", ...);
  page.registerSectionView("details", .......); // Calls Balanced.registerSectionView("customer/details", ...);
});

```