Move to make full use of ES6 features, and adopt ES7 async/await.

[MorganEPatch]

ECMAScript 2016 (aka ES6) has been out for months now, and Node 4 is fully compliant. ESLint, which I have been refusing to upgrade for this reason, in its newest version throws several hundred errors for not using ES6 features. Moving to ES6 makes our code not only more future-proof and standards-compliant (ES6 is part of a move to standardize JavaScript more than previously), but also smaller, faster, and easier to read, with the use of lambda functions, string interpolation, etc.

ECMAScript 2017 (ES7) also introduces a new feature which at this time is considered unlikely to change greatly before the standard is published, which is the keywords async and await. These will greatly clean up our asynchronous code and heavy use of callbacks, and hopefully make our code far easier to read and maintain.

These are rather large changes essentially involving refactoring the entire project. This is not a task to be taken lightly. But I do feel it is one that we need to do.