* sw-precache-webpack-plugin, SW registration, manifest.json

* Documentation + a few SW tweaks.

* Added an unregister method, too, just in case.

* More info for the READMEs.

* Add minify to SWPrecacheWebpackPlugin config

* Fix SWPrecacheWebpackPlugin typo

* Fix file references in READMEmd

* Add instructions for testing service-worker locally

* Review feedback

* Some additional PWA metadata

* Use sw-precache-webpack-plugin v0.9.1 for node >=4.0.0 support

* Review feedback.

* Add manifest.json context in a comment.

* Fix typo

* Downgrade to sw-precache-webpack-plugin 0.9.1

* Hide changes in README until 1.0

* Hide changes in User Guide until 1.0

* Hide more docs