Don't re-fetch section's assets

``SectionEditView`` defers rendering of the subviews for each
container until the assets are fetched.  On its initial render, it
fetches the assets.  However, this had the side-effect of re-fetching
the assets when switching between workflow steps.

This is unneccesary and actually causes problems with the model event
bindings in ``SectionAssetEditView`` since the model instance in
``SectionEditView.assets`` is no longer the same as
``SectionAssetEditView.model``.  One way this issue showed up was
in #764, where ``SectionAssetEditView`` instances did not re-render
when an asset was removed from a container by clicking on the remove icon.
Don't append unused asset view element

Don't append the unused asset view element to ``BuilderView``'s
element.  This is unneccessary because the rendering and appending
to the DOM for the unused asset view is now all handled by
``DrawerView``.
Code cleanup using jsHint

* Add missing semicolons
* Add "()" to object construction with "new"
* Remove trailing ','s in object property definitions
* Switch to dot notation when possible, when referencing object properties
Fix incorrect step in builder test