Add navigation support in news posts and archive page.

/CC @mpc-hc/developers 

Feedback is welcome.

![archive](https://cloud.githubusercontent.com/assets/349621/4528640/93d2b7ac-4d70-11e4-9f6a-66caf335eb30.png)

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![v1 7 7 is released mpc-hc](https://cloud.githubusercontent.com/assets/349621/4528642/9d387336-4d70-11e4-80f3-35ba87808d91.png)