[webcomponents]: The Shadow DOM spec is under heavy refactoring.

Dear WebAppazoids,

I would like to announce that the editor's draft of the Shadow DOM spec
(https://dvcs.w3.org/hg/webcomponents/raw-file/tip/spec/shadow/index.html)
is now under heavy refactoring.

The goal of the refactoring is to make the spec healthy, including the
followings:

- Use more formal definitions and notations.
- Make sure that the model and data structures, accompanying algorithms are
clearly defined.
- Make the spec more compact.

P.S. You can also see the original refactoring plan, which might be
obsolete, but some of the parts are still useful to know the goal of the
refactoring.
(
https://docs.google.com/document/d/1iuf2DgzwKfMTscAX_xsymO73NmZ4NVYvfyFgUU4YINo/edit?usp=sharing
)


-- 
Hayato