Update to layout to reflect widget behaviour

dtx-name="" elements now are exposed as DOMNode, not DOMCollection
Correctly handle haxe 3.1 differences, so fatalError works
Change dtx-name="" to expose as DOMNode, not DOMCollection

Also make the getter inline, now that it's just an array access
Update for reification in Haxe 3.1
If parent had a template, and this does not, do not recompute

This was causing crazy crazy errors