references in multimodal issue paper

Hi Lisa,

To the issue paper "Multi-modal Content Delivery<https://github.com/w3c/coga/blob/master/issue-papers/multi-modal.html>", I added references that (hopefully) are in the proper format, i.e., [[example]].

John

John Rochford<http://profiles.umassmed.edu/profiles/display/132901>
UMass Medical School/E.K. Shriver Center
Director, INDEX Program
Instructor, Family Medicine & Community Health
www.DisabilityInfo.org
Twitter: @ClearHelper<https://twitter.com/clearhelper>