Support multiple configurations from neutrinorc

[eliperelman]

This is a WIP!

Breaking change! This will allow us to finally support multiple configs from .neutrinorc.js by exporting an array.

module.exports = [
  {
    use: ['neutrino-preset-react']
  },
  {
    options: {
      source: 'server'
    },
    use: ['neutrino-preset-node']
  }
];

This works by spawning a new process for each configuration. I tried going down 2 other routes but faced difficulties that were near impossible to overcome in a good way.

Wanted to get this out there for feedback.

Fixes #308.

[edmorley]

Fixes #385.

s/385/308/ ? :-)

[eliperelman]

@edmorley lol oops.

[eliperelman]

Closing this in favor of a different solution.