[webvtt] Pull Request: Rename "middle" to "center" throughout for consistency with CSS

zcorpan has just submitted a new pull request for 
https://github.com/w3c/webvtt:

== Rename "middle" to "center" throughout for consistency with CSS ==
This affects align, position align, line align, and the DOM API.

Fixes https://www.w3.org/Bugs/Public/show_bug.cgi?id=25956.

See https://github.com/w3c/webvtt/pull/244

Received on Thursday, 5 November 2015 15:07:38 UTC