ESLint

[outoftime]

Add ESLint as a JavaScript validator. ESLint is very good at linting. Unfortunately it is not very good at providing useful parse error messages, which JSHint is. So we probably need to use both in concert.

At that point we can include extra validation for libraries being used, e.g. eslint-plugin-lodash, eslint-plugin-angular, eslint-plugin-react (where is the one for jQuery though???)