[ALOY-682] Alloy: Prevent default ID for a view's root element to be used by child element

Pull request for https://jira.appcelerator.org/browse/TC-2389

Why this? Well... never make the same mistake twice:
https://twitter.com/fokkezb/status/330260692575862785
https://twitter.com/FokkeZB/status/333164024290226176