ACTION-43: added user-agent-managed site-specific exception proposal to Editor's Draft

I've added the user-agent-managed site-specific exceptions proposal that we discussed on December 21 to the Editor's Draft: http://www.w3.org/2011/tracking-protection/drafts/tracking-dnt.html#exceptions

This is completion of ACTION-43.

This text includes inline references to the open issues we had around this proposal (including those raised during the call), hence the flood of new issue notifications that just hit all of your inboxes.

If there are other issues not included in that list, please raise them! And we would love any more feedback on this proposal now that you can see it in place in the Editor's Draft. Email discussion would be welcome, but I suggest that we could also add this to the agenda for the next call.

Thanks,
Nick