Make cue div CSS values 'vh' and 'vw' CSS units.

The specification has left and width as 'vw' CSS units
and top and height as 'vh' CSS units.
Remove incorrect arg param to convertCueToDOMTree().

For some reason we were passing filterJson to the
convertCueToDOMTree() function. This function doesn't accept
anything like that.
Add regions to processing model.
Add run processing model functionality to util.js
Rewrite cue2json.js.

- Rewrote cue2json to simplify it.
- Added functionality output JSON generated from the
processing model.
Add basic processing model test.
Update README.md

- Add info about the processing model now handling regions.
- Add info about the new cue2json.js script.
Refactor processing model.
Determine bidi of the first paragraph of a cue.
Update and refactor processing model.
fixed subtract topOffset from viewportAnchorY, regenerated
processing-model/basic.json
Merge pull request #124 from jespirit/top-fix

topOffset should be subtracted from viewportAnchorY
Add CueBoundingBoxes div to a region div instead of the box itself.
Update README.md JSON examples.
On error while streaming, display both chunks
All tests pass streaming chunks
- Need first line before parsing header.
- Handles CR-LF endings properly, passes all tests.
- Removed advance arg from collectNextLine.
- Simple test if header has bad double webvtt.
- Enter BADWEBVTT state on invalid header thus ignore further parsing.
Merge pull request #126 from jespirit/header-fix

Closes #125.
If region already has one child, set transition property
as per processing model step 12, substep 2
- Regenerated the JSON files for all tests
- Node object has empty list of child nodes
Merge pull request #128 from jespirit/region-fix

If region already had one child, set appropriate transition styles
Update AUTHORS file.