Use settings.region for paring region ids.
Store the cue setting 'region' property as 'regionId'.

RegionId is the name that the IDL of VTTCue specifies.
Store the cue's payload property as 'text'.

This is the name that the TextTrackCue IDL specifies for the
cuetext payload of the cue.
Flatten 'settings' property into the cue object.

This it to mimic how the VTTCue IDL specifies these values should
be stored.
Create VTTCues directly.

- Also added the new VTTCue as a dependency to grunt when installing
the lib for browser use. This ensures that browsers which don't
implement VTTCue yet can use the library.
- Bumped the package.json version number as this change breaks backwards
compatability.
Merge pull request #92 from RickEyre/texttrackcue

Store cue properties how the TextTrackCue and VTTCue IDLs specify