[WIP] Rewrite

_This is a massive PR that's most likely not reviewable, therefore it should be considered a working branch for the website's rewrite._

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### Goals of Rewrite

This rewrite of the site has the follow as the primary goals:

- Align with user stories.
- Simplify site, reducing pages, and clearer content organization.
- Make it easier to add examples.
- Make examples work and format properly.
- Use React on server and client to build UI.
- Use ES6 modules for shared and client code.
- Have a dev process that doesn't require server restarts.

### New Features

- i18n messages are now in pre-formatted YAML.
- Examples are now in their own dirs `[type]/[name]`.
- Examples' JavaScript context object is now in sync with its source code display.
- New examples and messages can be added without restarting server.

### TODOs

- [ ] Add styling for content pages.
- [ ] Update examples infrastructure to support Dust and React.
- [ ] Add Dust examples.
- [ ] Add React examples.
- [ ] Add back some of the content we can keep from old version.
- [ ] Fill-in Home page content sections.
- [ ] Add favicon.
- [ ] Switch to [Highlights](https://github.com/atom/highlights) for syntax highlighting.