Code organization and reusable assets

The foundation of our way of writing reusable and testable D3 code is from Mike Bostock's blog article, Towards Reusable Charts, at http://bost.ocks.org/mike/chart/. At its core, it sets out to implement charts as closures with getter and setter methods. This makes the code more readable and simple for testing. It is actually a great idea to read this article before continuing, as we can take some of our career experiences and extend these concepts a little further. The project structure is organized to achieve several goals.