Initial implementation of Docs Web Server

This pull request creates an Express webserver that we can use for the JS-Intl docs website. The server is pretty bare-bones atm but shows an example of server-rendered content using the Intl Handlebars helpers. We can build on this example when creating similar ones for React and Dust.

![](http://f.cl.ly/items/42061J1Q090X0l3L3M3F/Screen%20Shot%202014-06-03%20at%204.28.48%20PM.png)

There are currently two routes on the server:

* `/` Just has some content that I pulled from `introduction.md`.
* `/handlebars/` has an inline example of server-rendered content using the Intl Handlebars helpers.

We need to add the remaining Markdown docs as Handlebars pages. We also need to create more documentation around using these modules, with inline examples.

## Folder Structure 

The folder structure that I'm using for internationalization is as follows:

There's a root level `i18n/` folder, which contains the example sub-folders. Right now, it only contains a `handlebars/` folder, but you can imagine also having a `react/` and `dust/` folder. I have the language.json files inside these sub-folders. I figured that even if we have multiple inline examples, they can still be served via the same language.json file. 

To change the language for the server-rendered example, you'll currently need to go into `app.js` and change the `default locale` setting. For example:
```js
app.set('default locale', 'fr-FR');
```
will make the handlebars example render in French. 

## Other useful things

* Have Handlebars helpers for easy inline code blocks
* RainbowJS (via Bower) for syntax highlighting
* some basic CSS

As you guys need more helpers, you can [look at the work](https://github.com/yui/pure-site/blob/master/lib/helpers.js) we've done on the Pure Site re. Handlebars Helpers.

## Try it out
Pull down this branch locally. Then `npm install`, `npm start`.

## Tasks before merging this in
- [ ] Port the existing MD files on `master` to handlebars https://github.com/yahoo/js-intl-docs/issues/2
Just a note that we decided in the post-standup meeting to preserve the /handlebars, /react etc routes.