automate the push to gh-pages

[dherman]

Automate the pushing to gh-pages, using Travis. See:

• https://github.com/whatwg/streams/blob/master/deploy-gh-pages.sh
• https://github.com/whatwg/streams/blob/master/.travis.yml
• http://docs.travis-ci.com/user/encryption-keys/
• https://medium.com/@nthgergo/publishing-gh-pages-with-travis-ci-53a8270e87db

[dherman]

Doh, maybe won't work? Domenic was doing it via the online bikeshed service and posting via curl, but that doesn't allow you to provide custom .include files.

[dherman]

If Travis lets us install bikeshed locally maybe it'll work, but I don't know.

[dherman]

Now that we don't rely on custom .include files we can just use [https://github.com/whatwg/streams/blob/master/deploy-gh-pages.sh](Domenic's hacks) for Travis automation.

[caridy]

I will take care of this one now that we have the build in place.