Changes

* [[vCard4]]: go through my critiques of draft 13 and check draft 15 accordingly, document which feedback was accepted or not (document email threads accordingly and decide on follow-up), review draft 15 thoroughly and write-up draft 15 review.

* [[Tantek-Mozilla-projects#DOM_API_vendor_prefixing|DOM API vendor prefixing]]: discussing internally at Mozilla to build consensus, set a good example.

See below for more details on each.