[TIMOB-19085] Windows: Adding items to a ListSection after creation of ListView doesn't update UI

In testing the RSS Reader sample, I'm seeing nothing happen once we do get the RSS feed fetched. Once I loaded everything up in Debug mode in VS2013, I see the following logs when it should be showing the new items in the ListView:

TitaniumKit 000000087 Fri Jun 26 16:28:40 2015 WARN: ListSection::items_set_notify: Unimplemented.

Basically, our code works fine if all the items are created first, then added to sections, then the ListView is created from the pre-populated section. But if you generate a ListView with one section, and add items to it later async, nothing actually happens visually. We haven't hooked all that code up to do anything. We have methods for modifying the sections on a view, and I think that should work fine post-create, but the item manipulation at the section level just never triggers the view to add them.