Escape key closes overlay after confirming with delegate. Code and unit tests, but the key composer just never actually sends us events
Overlay correctly claims and surrenders activeTarget.
Clean up and document formerly-duplicated code for dismissing overlay.
Overlay code review fixes:

- Document and clean up workaround for KeyComposer event firing on component rather than composer.
- Add test for activeTarget handling.
Overlays should not leak events to previous activeTarget.
Yes it should.
Guard against non-component candidate active target
Active target should only be managed when Modal

We do not know the developers intention in non-modal cases.
Merge pull request #1303 from asolove/escape-closes-overlay

Escape closes overlay