Update folder structure

[justingreenberg]

Resolves #169

So, this ended up being a pretty big PR. My goals were twofold:

• Simplify the structure so people using this as a reference can quickly scan through and identify the moving parts or relevant implementations with minimal effort
• For those using this as a boilerplate, establish well defined contact points between the router, containers and components with maintainable conventions

New ./src directory tree (browse)

./src
├── api
│   └── actions
├── components
│   ├── __tests__
│   ├── CounterButton
│   ├── GithubButton
│   ├── InfoBar
│   ├── MiniInfoBar
│   ├── SurveyForm
│   └── WidgetForm
├── containers
│   ├── __tests__
│   ├── About
│   ├── App
│   ├── Home
│   ├── Login
│   ├── LoginSuccess
│   ├── NotFound
│   ├── RequireLogin
│   ├── Survey
│   └── Widgets
├── helpers
├── redux
│   ├── middleware
│   └── modules
└── utils

If these changes are too drastic, I can just always roll them into a new seed project or something

Known bug: When server-side rendering the /widgets route and the API throws, the router was throwing an error at server.js#L66 and express was responding with a empty JSON object (presumably the failed results). I couldn't identify the cause of this behavior, so right now if the server detects an issue with data fetching during a server-side render, we just sending app and rehydrating store on client.

Any feedback would be greatly appreciated! Thanks again 😃