Position styling on outter caption box should be 'relative'.
Cue setting percent values now allow decimal points.
Release v0.6.4
Output JSON in a deterministic, alphabetical, way.

In this way if we change the order in which we set properties it
won't change the JSON of the test files and bloat our commits for
no reason.
Update README for CSS extension explanation.
Update README CSS extendsion explanation to be bold.
Manually calculate font size.

Using the height of the containing div we can calculate
the font size. This is easier then doing as the spec
says and using 'vh' and redefining the viewport as the
video container.
Release v0.6.5
Rename *BoundingBox classes to *StyleBox.

This makes it more clear what these classes are actually doing.
Implement the algorithm for finding a cues best position.

- This supports horizontal text only. It needs a few tweaks
to fully support vertical text.
- The test suite has been altered to balance the computed values of
processing model tests since they will be different on different
platforms. This means calculating offsets based on differences in
computed line heights and applying the offsets to the different
CSS position values.
Release v0.7.0