Upgrade website

I recently opened an [issue](https://github.com/chocolatey/chocolatey/issues/329) in the main Chocolatey repo talking about making a new Github page. This the said site, which is a general documentation website for Chocolatey.

**Content:**

I went through the wiki and picked the parts that I as a new user would like to see. The goal was to make it as comprehensive as possible and pointing to the wiki where more information was available.

**Technical features:**

- Uses Jekyll with [kramdown](http://kramdown.rubyforge.org/) as a Markdown generator.
- Uses Sass coupled with [BEM](http://csswizardry.com/2013/01/mindbemding-getting-your-head-round-bem-syntax/).
- Fully responsive with an optimized mobile navigation.
- Syntax highlighting (although I had to use `bash` and `php` for the PowerShell stuff, but it works out).

A demo is still available here: http://ellengummesson.com/choco-docs/