Fix ui bindings for Collection and Composite Views

Fixes #1502.

Not going to lie, this was a bigger / more invasive change than I expected when I went in here.

This fixes a couple things that broke:
1. collectionView now invokes bindUIelements after rendering its children
2. compositeView now invokes bindUIelements after rendering its children

Interesting to note:
+ compositeView also invokes bindUIelements before rendering its children because childViewContainer could have ui interpolation


how can a length be an instance of ?