[ttml2] Pull Request: Issue 0148 clarify visibility hidden

skynavga has just submitted a new pull request for 
https://github.com/w3c/ttml2:

== Issue 0148 clarify visibility hidden ==
See #148.

See https://github.com/w3c/ttml2/pull/207

Received on Tuesday, 25 October 2016 21:14:01 UTC