each-*: when rebinding, bind any existing views in @iterated

Prior to this change, an each-* bound view could be rebound but only at the array level.  i.e.: any existing views that had been realized weren’t being bound again.  This let you realize changes to the array itself, but changes to existing elements of the array were not being reflected into the DOM.

I've also added a few tests around some of the each-* binder - hopefully in location you would have expected.

I should also mention that, while I drink coffee, I don't write it - hopefully I've fumbled my way the correct solution here.