ES6 as the default syntax

[stavarotti]

I am half way through making ES6 changes such as using fat arrow functions in place of _this. A few questions before I move forward (should have asked before embarking on this:-)):

• Since Babel 5, I write all my apps using ES6 syntax such as fat arrows and destructuring. Do you want me to continue on this path?
• If yes to the above, do we want to have a brief mention that we are using ES6 syntax beyond the import and export?
• Lastly, we probably want to limit the constructs introduced. What is a fair set that should be considered normal?