[ttml1] Add note clarifying meaning of tts:direction 'ltr' and 'rtl' in vertical writing modes.

skynavga has just created a new issue for 
https://github.com/w3c/ttml1:

== Add note clarifying meaning of tts:direction 'ltr' and 'rtl' in 
vertical writing modes. ==
See also #227.

Please view or discuss this issue at 
https://github.com/w3c/ttml1/issues/228 using your GitHub account

Received on Thursday, 12 January 2017 11:50:57 UTC