- force the time dilation to 1.0 for the Widget tests, so that a local
change doesn't break all the tests during development.
- add missing license block to all the files.
- set ui.window.onBeginFrame to null when you use WidgetTester, so that
the engine doesn't trigger any confusing frames after our fake frames.
When we reactivate a subtree that had a global key, we weren't updating the
parent data because:
1) The child wasn't in the tree when we updated the parent data element.
2) The activated child didn't go through mount (just through update).
This patch moves the parent data update work to when we attach the render
object, which we do both during mount and when reactivating a child.
Fixes#345
