This version includes a more complete selection of ES2015 polyfills
that I started used across the code base, for instance by replacing
`$.trim(str)` by `str.trim()`.
Replace the old (and broken) jshint + jscsrc by eslint and configure
it to support some of the ES6 features.
The command `eslint` currently has one error which is a bug that was
discovered by its static analysis and should be fixed (usage of a
dead object).