WIP: Style blocks

[gkatsev]

Expects a standalone version of css and then requires the integration to pass parser.styles into processCues, but this still needs to be updated.

TODO:

• STYLE blocks
• can't have style blocks once seen cues
• filter allowed properties
• classes
• webvtt object
  • voice
  • italics
  • bold
  • underline
  • ruby
  • ruby text
  • language
  • other objects

[gjanblaszczyk]

Hi Gary, What is the status of this PR? Are you planning to continue work on this PR this year?

[gkatsev]

Yes, I'd like to get this done some time this year, though, it likely needs to be re-done based on the refactor in master. Another thing is to decide what to do about the parsing of the CSS. I don't want to include it by default. Also, not sure if the css package is the best thing for this or if there's something better/lighter to use.
Also, I would say that the regions work is likely a higher priority for me, especially since Chrome is working on native support for this finally.