* add 'next' api

* add render APIs

* add 'as' prop to Link

* check Accept header to serve json response

* check if response was finished on getInitialProps call

* move server/app to server/index

* load webpack-hot-middleware-client by absolute path

* server: options for testing

* add tests

* example: improve

* server: make dir optional

* fix client routing

* add parameterized routing example

* link: fix display url

* Add custom-server-express example (#352)

* Add custom-server-express example

* Remove extraneous nexts in express routes defs

* Update next config in server.js

* Handle accept headers totally inside Next.js (#385)

* Handle accept headers totally inside Next.js
Now user doesn't need to handle it anymore.

* Move json pages serving to /_next/pages base path.

* Join paths correctly.

* remove next/render

* Register the service worker.

* Update prefetcher code to do prefetching.

* Implement the core prefetching API.
support "import <Link>, { prefetch } from 'next/prefetch'"

* Implement a better communication system with the service worker.

* Add a separate example for prefetching

* Fix some typos.

* Initiate service worker support even prefetching is not used.
This is pretty important since initiating will reset the cache.
If we don't do this, it's possible to have old cached resources
after the user decided to remove all of the prefetching logic.
In this case, even the page didn't prefetch it'll use the
previously cached pages. That because of there might be a already running
service worker.

* Use url module to get pathname.

* Move prefetcher code to the client from pages
Now we also do a webpack build for the prefetcher code.

* Add prefetching docs to the README.md

* Fix some typo.

* Register service worker only if asked to prefetch
We also clean the cache always, even we initialize
the service worker or not.

* Added linting using standard

* Linting on test