[media] Further edits to the Media Multitrack API

Hi all,

In today's call we discussed that we want to move the Media Multitrack
API proposal at http://www.w3.org/WAI/PF/HTML/wiki/Media_MultitrackAPI
forward to a poll with the accessibility group next week.

There were some issues raised with the wording of the proposal, so we
decided to have a further editing period between now and Tuesday
morning and post the poll on Tuesday morning.

Please make your edits at
http://www.w3.org/WAI/PF/HTML/wiki/Media_MultitrackAPI and/or post
your concerns to the list for discussion and formulation of improved
wordings.

Best Regards,
Silvia.