Remove stage-0 Babel preset about neutrino

[eliperelman]

Fixed in #10.

[atoiv]

For anyone wondering how to use the removed stage-0 babel-preset with react preset, the following custom config does seem to do the trick:

// my-custom-config.js
const merge = require('deepmerge');

module.exports = neutrino => {
  neutrino.config
    .module
      .rule('compile')
        .loader('babel', ({ options }) => {
          return {
            options: merge(options, {
              presets: [
                require.resolve('babel-preset-stage-0'),
              ],
            })
          };
        });
}

For me, the missing plugin was stage-2 babel-plugin-transform-class-properties, for class properties. Which in react's context is handy for auto binding event handlers, and using propTypes as static class properties. But there's probably other features in stage-0 I'd want to use as well.