Move TouchEvents spec tweaking to GitHub?

Should we move tweaks to the v1-errata and extensions note to GitHub?  I
think that would be easier for collaboration than hg (easier to track
changes, review PRs, and avoids people having to learn something new).

Art, if we decide to publish an official errata, would the detailed change
history being in github make that much more difficult policy-wise?

Jacob, is it better for a contributor to the W3C GitHub project to create
the repo there?  Or can I just create one that w3c could eventually
adopt/clone?

Thanks,
   Rick