[webvtt] Pull Request: Drop line: and position: settings with invalid linealign/colalign

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

== Drop line: and position: settings with invalid linealign/colalign 
==
Fixes #336.

See https://github.com/w3c/webvtt/pull/337

Received on Friday, 3 March 2017 11:40:13 UTC