Add references to Promise spec

As requested:
http://lists.w3.org/Archives/Public/public-fx/2014OctDec/0025.html

Generated from:

commit 4c1f3cede680f1fb1d5a24a54fe58256cbd08878
Author: Brian Birtles <birtles@gmail.com>
Date:   Mon Oct 27 15:11:13 2014 +0900

    Add references to Promise spec

    As requested:
    http://lists.w3.org/Archives/Public/public-fx/2014OctDec/0025.html