Navigator pushState at getting started

- Move `tutorial-navigator` to **Getting started** page.
- Add `pushState` and hashed routes for `tutorial-navigator`.
- Remove from sidebar all tutorials included in `tutorial-navigator`.
- Update getting started texts.


![image](https://cloud.githubusercontent.com/assets/367429/3221276/b105dcec-f009-11e3-8250-c9689ff8230d.png)

That's what I meant for *this version*. Right now this is not SEO friendly since there are no **links** pointing to any of the tutorial routes neither those can be found on the `sitemap`.

Its a point taken that this **must** be SEO driven but I'd wait for a next release with the new tutorial docs.