[webcomponents] Stubbed out Slots proposal. (#52)

@rniwa @hayatoito PTAL. Just a stub to start concretizing the proposal.
You can view, comment on, or merge this pull request online at:

  https://github.com/w3c/webcomponents/pull/52

-- Commit Summary --

  * Stubbed out Slots proposal.

-- File Changes --

    A proposals/Slots-Proposal.md (24)

-- Patch Links --

https://github.com/w3c/webcomponents/pull/52.patch
https://github.com/w3c/webcomponents/pull/52.diff

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Reply to this email directly or view it on GitHub:
https://github.com/w3c/webcomponents/pull/52