Add a README for navigator.connect

This way the github landing page can direct people to where they want to go.
Add some more links to the document header.

* A link to the canonical editor's draft
* Links to the github repository so people can file bugs and send patches.
Add an initial use-cases document.
Link to the use cases from the README.
Add an "Offline Analytics" use case.
Add a shared web-fonts use case.
Add a description of the "Tubes" use of navigator.connect.
Separate out the basic "Tubes" use case
from the strategies to prevent developers from depending on experimental APIs.
Merge pull request #1 from jyasskin/through-bedrock

Add a description of the "Tubes" use of navigator.connect.
Added Cloud Storage Platforms section to Use Cases
Used tidy to clean up use-cases.html
Changed Shared Fonts section to address why browser cache falls short
Fixed grep error changing ServiceWorker link
Changed 'blunders' to different language in Shared Fonts section
Merge pull request #6 from jyasskin/readme

Add a README for navigator.connect
Merge pull request #9 from jyasskin/header-info

Add some more links to the document header.
Merge pull request #10 from jyasskin/use-cases

Add a Use Cases document to the repository.
Merge pull request #11 from jakeleichtling/use-cases

Changed Shared Fonts section to address why browser cache falls short
Changed Shared Fonts section to not overstate browser cache disadvantages
Added stale-while-revalidate sentence to Shared Fonts