Don't try to decode data if parse is handed none.

This bug was found when integrating vtt.js into Gecko.
Updated the lang tests with correct utf-8

Also wired tests into the test harness
Merge pull request #93 from gandriy11/test_lang

Testing language files Closes #46
Merge pull request #96 from RickEyre/parse-fix

Don't try to decode data if parse is handed none.
Add a test for cue IDs.
Initial implementation of the processing model.

This patch implements support for processing multiple VTTCues
from multiple TextTracks at once as well as applying the initial
CSS positioning and styles to the VTTCues once they are converted
to a DOM tree.
Wrap vtt.js in a function expression.

Also export WebVTTParser on the global whether we
are running in node or otherwise. This was suggested
by Dave on bug 895091 to take care of the node,
web page, and browser use cases.
Bulk README.md updates.

Documentation for processCues(), VTTRegion bundled in the
web page polyfill dist, and updates to the JSON test file
example.
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