feat(ElementPanel): display scope properties for children of DocumentFragments

Sort of related to https://github.com/angular/angular.js/pull/6637 ---
Currently, jqLite#inheritedData() will not find data if it needs to cross
through document fragment barriers, such as the Shadow DOM barrier. This patch
allows batarang to figure this out.

In addition, it provides some tests for the angularjs properties sidebar of
the element panel, which were missing previously.

Closes #104