BHV-8502: In enyo.Popup, make eventsToCapture a concat'able property.

Doing this because we now have two different cases in Moonstone where subkinds of enyo.Popup need to capture additional events.

Making enyo.Popup noDefer: true so that we can add the required concat() method to its constructor.

Enyo-DCO-1.1-Signed-Off-By: Gray Norton (gray.norton@lge.com)
Merge pull request #749 from enyojs/BHV-8502-graynorton

BHV-8502: In enyo.Popup, make eventsToCapture a concat'able property.